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* Merge tag 'mm-nonmm-stable-2024-03-14-09-36' of ↵Linus Torvalds2024-03-141-0/+9
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: - Kuan-Wei Chiu has developed the well-named series "lib min_heap: Min heap optimizations". - Kuan-Wei Chiu has also sped up the library sorting code in the series "lib/sort: Optimize the number of swaps and comparisons". - Alexey Gladkov has added the ability for code running within an IPC namespace to alter its IPC and MQ limits. The series is "Allow to change ipc/mq sysctls inside ipc namespace". - Geert Uytterhoeven has contributed some dhrystone maintenance work in the series "lib: dhry: miscellaneous cleanups". - Ryusuke Konishi continues nilfs2 maintenance work in the series "nilfs2: eliminate kmap and kmap_atomic calls" "nilfs2: fix kernel bug at submit_bh_wbc()" - Nathan Chancellor has updated our build tools requirements in the series "Bump the minimum supported version of LLVM to 13.0.1". - Muhammad Usama Anjum continues with the selftests maintenance work in the series "selftests/mm: Improve run_vmtests.sh". - Oleg Nesterov has done some maintenance work against the signal code in the series "get_signal: minor cleanups and fix". Plus the usual shower of singleton patches in various parts of the tree. Please see the individual changelogs for details. * tag 'mm-nonmm-stable-2024-03-14-09-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits) nilfs2: prevent kernel bug at submit_bh_wbc() nilfs2: fix failure to detect DAT corruption in btree and direct mappings ocfs2: enable ocfs2_listxattr for special files ocfs2: remove SLAB_MEM_SPREAD flag usage assoc_array: fix the return value in assoc_array_insert_mid_shortcut() buildid: use kmap_local_page() watchdog/core: remove sysctl handlers from public header nilfs2: use div64_ul() instead of do_div() mul_u64_u64_div_u64: increase precision by conditionally swapping a and b kexec: copy only happens before uchunk goes to zero get_signal: don't initialize ksig->info if SIGNAL_GROUP_EXIT/group_exec_task get_signal: hide_si_addr_tag_bits: fix the usage of uninitialized ksig get_signal: don't abuse ksig->info.si_signo and ksig->sig const_structs.checkpatch: add device_type Normalise "name (ad@dr)" MODULE_AUTHORs to "name <ad@dr>" dyndbg: replace kstrdup() + strchr() with kstrdup_and_replace() list: leverage list_is_head() for list_entry_is_head() nilfs2: MAINTAINERS: drop unreachable project mirror site smp: make __smp_processor_id() 0-argument macro fat: fix uninitialized field in nostale filehandles ...
| * panic: add option to dump blocked tasks in panic_printFeng Tang2024-02-221-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For debugging kernel panics and other bugs, there is already an option of panic_print to dump all tasks' call stacks. On today's large servers running many containers, there could be thousands of tasks or more, and this will print out huge amount of call stacks, taking a lot of time (for serial console which is main target user case of panic_print). And in many cases, only those several tasks being blocked are key for the panic, so add an option to only dump blocked tasks' call stacks. [akpm@linux-foundation.org: clarify documentation a little] Link: https://lkml.kernel.org/r/20240202132042.3609657-1-feng.tang@intel.com Signed-off-by: Feng Tang <feng.tang@intel.com> Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * panic: suppress gnu_printf warningBaoquan He2024-02-221-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | with GCC 13.2.1 and W=1, there's compiling warning like this: kernel/panic.c: In function `__warn': kernel/panic.c:676:17: warning: function `__warn' might be a candidate for `gnu_printf' format attribute [-Wsuggest-attribute=format] 676 | vprintk(args->fmt, args->args); | ^~~~~~~ The normal __printf(x,y) adding can't fix it. So add workaround which disables -Wsuggest-attribute=format to mute it. Link: https://lkml.kernel.org/r/20240107091641.579849-1-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | panic: Flush kernel log buffer at the endJohn Ogness2024-02-071-0/+8
|/ | | | | | | | | | | | | | | | | If the kernel crashes in a context where printk() calls always defer printing (such as in NMI or inside a printk_safe section) then the final panic messages will be deferred to irq_work. But if irq_work is not available, the messages will not get printed unless explicitly flushed. The result is that the final "end Kernel panic" banner does not get printed. Add one final flush after the last printk() call to make sure the final panic messages make it out as well. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20240207134103.1357162-14-john.ogness@linutronix.de Signed-off-by: Petr Mladek <pmladek@suse.com>
* panic: use atomic_try_cmpxchg in panic() and nmi_panic()Uros Bizjak2023-10-041-9/+13
| | | | | | | | | | | | | | | | | | | Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old in panic() and nmi_panic(). x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after cmpxchg (and related move instruction in front of cmpxchg). Also, rename cpu variable to this_cpu in nmi_panic() and try to unify logic flow between panic() and nmi_panic(). No functional change intended. [ubizjak@gmail.com: clean up if/else block] Link: https://lkml.kernel.org/r/20230906191200.68707-1-ubizjak@gmail.com Link: https://lkml.kernel.org/r/20230904152230.9227-1-ubizjak@gmail.com Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* panic: Reenable preemption in WARN slowpathLukas Wunner2023-09-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit: 5a5d7e9badd2 ("cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG") amended warn_slowpath_fmt() to disable preemption until the WARN splat has been emitted. However the commit neglected to reenable preemption in the !fmt codepath, i.e. when a WARN splat is emitted without additional format string. One consequence is that users may see more splats than intended. E.g. a WARN splat emitted in a work item results in at least two extra splats: BUG: workqueue leaked lock or atomic (emitted by process_one_work()) BUG: scheduling while atomic (emitted by worker_thread() -> schedule()) Ironically the point of the commit was to *avoid* extra splats. ;) Fix it. Fixes: 5a5d7e9badd2 ("cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG") Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/r/3ec48fde01e4ee6505f77908ba351bad200ae3d1.1694763684.git.lukas@wunner.de
* mm: remove arguments of show_mem()Kefeng Wang2023-08-181-1/+1
| | | | | | | | | | | | | | | All callers of show_mem() pass 0 and NULL, so we can remove the two arguments by directly calling __show_mem(0, NULL, MAX_NR_ZONES - 1) in show_mem(). Link: https://lkml.kernel.org/r/20230630062253.189440-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* panic: hide unused global functionsArnd Bergmann2023-06-091-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Building with W=1 shows warnings about two functions that have no declaration or caller in certain configurations: kernel/panic.c:688:6: error: no previous prototype for 'warn_slowpath_fmt' [-Werror=missing-prototypes] kernel/panic.c:710:6: error: no previous prototype for '__warn_printk' [-Werror=missing-prototypes] Enclose the definition in the same #ifdef check as the declaration. Link: https://lkml.kernel.org/r/20230517131102.934196-8-arnd@kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Eric Paris <eparis@redhat.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael@kernel.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* cpu: Mark nmi_panic_self_stop() __noreturnJosh Poimboeuf2023-04-141-1/+1
| | | | | | | | | In preparation for improving objtool's handling of weak noreturn functions, mark nmi_panic_self_stop() __noreturn. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/316fc6dfab5a8c4e024c7185484a1ee5fb0afb79.1681342859.git.jpoimboe@kernel.org
* cpu: Mark panic_smp_self_stop() __noreturnJosh Poimboeuf2023-04-141-1/+1
| | | | | | | | | In preparation for improving objtool's handling of weak noreturn functions, mark panic_smp_self_stop() __noreturn. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/92d76ab5c8bf660f04fdcd3da1084519212de248.1681342859.git.jpoimboe@kernel.org
* panic: fix the panic_print NMI backtrace settingGuilherme G. Piccoli2023-03-021-18/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 8d470a45d1a6 ("panic: add option to dump all CPUs backtraces in panic_print") introduced a setting for the "panic_print" kernel parameter to allow users to request a NMI backtrace on panic. Problem is that the panic_print handling happens after the secondary CPUs are already disabled, hence this option ended-up being kind of a no-op - kernel skips the NMI trace in idling CPUs, which is the case of offline CPUs. Fix it by checking the NMI backtrace bit in the panic_print prior to the CPU disabling function. Link: https://lkml.kernel.org/r/20230226160838.414257-1-gpiccoli@igalia.com Fixes: 8d470a45d1a6 ("panic: add option to dump all CPUs backtraces in panic_print") Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Cc: <stable@vger.kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Feng Tang <feng.tang@intel.com> Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Kees Cook <keescook@chromium.org> Cc: Michael Kelley <mikelley@microsoft.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUGPeter Zijlstra2023-01-311-0/+5
| | | | | | | | | | | | | | In order to avoid WARN/BUG from generating nested or even recursive warnings, force rcu_is_watching() true during WARN/lockdep_rcu_suspicious(). Notably things like unwinding the stack can trigger rcu_dereference() warnings, which then triggers more unwinding which then triggers more warnings etc.. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230126151323.408156109@infradead.org
* Merge tag 'hardening-v6.2-rc1-fixes' of ↵Linus Torvalds2022-12-231-2/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull kernel hardening fixes from Kees Cook: - Fix CFI failure with KASAN (Sami Tolvanen) - Fix LKDTM + CFI under GCC 7 and 8 (Kristina Martsenko) - Limit CONFIG_ZERO_CALL_USED_REGS to Clang > 15.0.6 (Nathan Chancellor) - Ignore "contents" argument in LoadPin's LSM hook handling - Fix paste-o in /sys/kernel/warn_count API docs - Use READ_ONCE() consistently for oops/warn limit reading * tag 'hardening-v6.2-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: cfi: Fix CFI failure with KASAN exit: Use READ_ONCE() for all oops/warn limit reads security: Restrict CONFIG_ZERO_CALL_USED_REGS to gcc or clang > 15.0.6 lkdtm: cfi: Make PAC test work with GCC 7 and 8 docs: Fix path paste-o for /sys/kernel/warn_count LoadPin: Ignore the "contents" argument of the LSM hooks
| * exit: Use READ_ONCE() for all oops/warn limit readsKees Cook2022-12-161-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use a temporary variable to take full advantage of READ_ONCE() behavior. Without this, the report (and even the test) might be out of sync with the initial test. Reported-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/lkml/Y5x7GXeluFmZ8E0E@hirez.programming.kicks-ass.net Fixes: 9fc9e278a5c0 ("panic: Introduce warn_limit") Fixes: d4ccd54d28d3 ("exit: Put an upper limit on how often we can oops") Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Jann Horn <jannh@google.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Petr Mladek <pmladek@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Marco Elver <elver@google.com> Cc: tangmeng <tangmeng@uniontech.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Kees Cook <keescook@chromium.org>
* | Merge tag 'hardening-v6.2-rc1' of ↵Linus Torvalds2022-12-141-3/+42
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull kernel hardening updates from Kees Cook: - Convert flexible array members, fix -Wstringop-overflow warnings, and fix KCFI function type mismatches that went ignored by maintainers (Gustavo A. R. Silva, Nathan Chancellor, Kees Cook) - Remove the remaining side-effect users of ksize() by converting dma-buf, btrfs, and coredump to using kmalloc_size_roundup(), add more __alloc_size attributes, and introduce full testing of all allocator functions. Finally remove the ksize() side-effect so that each allocation-aware checker can finally behave without exceptions - Introduce oops_limit (default 10,000) and warn_limit (default off) to provide greater granularity of control for panic_on_oops and panic_on_warn (Jann Horn, Kees Cook) - Introduce overflows_type() and castable_to_type() helpers for cleaner overflow checking - Improve code generation for strscpy() and update str*() kern-doc - Convert strscpy and sigphash tests to KUnit, and expand memcpy tests - Always use a non-NULL argument for prepare_kernel_cred() - Disable structleak plugin in FORTIFY KUnit test (Anders Roxell) - Adjust orphan linker section checking to respect CONFIG_WERROR (Xin Li) - Make sure siginfo is cleared for forced SIGKILL (haifeng.xu) - Fix um vs FORTIFY warnings for always-NULL arguments * tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (31 commits) ksmbd: replace one-element arrays with flexible-array members hpet: Replace one-element array with flexible-array member um: virt-pci: Avoid GCC non-NULL warning signal: Initialize the info in ksignal lib: fortify_kunit: build without structleak plugin panic: Expose "warn_count" to sysfs panic: Introduce warn_limit panic: Consolidate open-coded panic_on_warn checks exit: Allow oops_limit to be disabled exit: Expose "oops_count" to sysfs exit: Put an upper limit on how often we can oops panic: Separate sysctl logic from CONFIG_SMP mm/pgtable: Fix multiple -Wstringop-overflow warnings mm: Make ksize() a reporting-only function kunit/fortify: Validate __alloc_size attribute results drm/sti: Fix return type of sti_{dvo,hda,hdmi}_connector_mode_valid() drm/fsl-dcu: Fix return type of fsl_dcu_drm_connector_mode_valid() driver core: Add __alloc_size hint to devm allocators overflow: Introduce overflows_type() and castable_to_type() coredump: Proactively round up to kmalloc bucket size ...
| * panic: Expose "warn_count" to sysfsKees Cook2022-12-021-2/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since Warn count is now tracked and is a fairly interesting signal, add the entry /sys/kernel/warn_count to expose it to userspace. Cc: Petr Mladek <pmladek@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: tangmeng <tangmeng@uniontech.com> Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221117234328.594699-6-keescook@chromium.org
| * panic: Introduce warn_limitKees Cook2022-12-021-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Like oops_limit, add warn_limit for limiting the number of warnings when panic_on_warn is not set. Cc: Jonathan Corbet <corbet@lwn.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Petr Mladek <pmladek@suse.com> Cc: tangmeng <tangmeng@uniontech.com> Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: linux-doc@vger.kernel.org Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221117234328.594699-5-keescook@chromium.org
| * panic: Consolidate open-coded panic_on_warn checksKees Cook2022-12-021-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Several run-time checkers (KASAN, UBSAN, KFENCE, KCSAN, sched) roll their own warnings, and each check "panic_on_warn". Consolidate this into a single function so that future instrumentation can be added in a single location. Cc: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ben Segall <bsegall@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Gow <davidgow@google.com> Cc: tangmeng <tangmeng@uniontech.com> Cc: Jann Horn <jannh@google.com> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Petr Mladek <pmladek@suse.com> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: kasan-dev@googlegroups.com Cc: linux-mm@kvack.org Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Link: https://lore.kernel.org/r/20221117234328.594699-4-keescook@chromium.org
| * panic: Separate sysctl logic from CONFIG_SMPKees Cook2022-12-011-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation for adding more sysctls directly in kernel/panic.c, split CONFIG_SMP from the logic that adds sysctls. Cc: Petr Mladek <pmladek@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: tangmeng <tangmeng@uniontech.com> Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221117234328.594699-1-keescook@chromium.org
* | panic: use str_enabled_disabled() helperAndy Shevchenko2022-11-181-2/+3
|/ | | | | | | | Use str_enabled_disabled() helper instead of open coding the same. Link: https://lkml.kernel.org/r/20221008195914.54199-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* kernel/panic: Drop unblank_screen callDaniel Vetter2022-09-011-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | console_unblank() does this too (called in both places right after), and with a lot more confidence inspiring approach to locking. Reconstructing this story is very strange: In b61312d353da ("oops handling: ensure that any oops is flushed to the mtdoops console") it is claimed that a printk(" "); flushed out the console buffer, which was removed in e3e8a75d2acf ("[PATCH] Extract and use wake_up_klogd()"). In todays kernels this is done way earlier in console_flush_on_panic with some really nasty tricks. I didn't bother to fully reconstruct this all, least because the call to bust_spinlock(0); gets moved every few years, depending upon how the wind blows (or well, who screamed loudest about the various issue each call site caused). Before that commit the only calls to console_unblank() where in s390 arch code. The other side here is the console->unblank callback, which was introduced in 2.1.31 for the vt driver. Which predates the console_unblank() function by a lot, which was added (without users) in 2.4.14.3. So pretty much impossible to guess at any motivation here. Also afaict the vt driver is the only (and always was the only) console driver implementing the unblank callback, so no idea why a call to console_unblank() was added for the mtdooops driver - the action actually flushing out the console buffers is done from console_unlock() only. Note that as prep for the s390 users the locking was adjusted in 2.5.22 (I couldn't figure out how to properly reference the BK commit from the historical git trees) from a normal semaphore to a trylock. Note that a copy of the direct unblank_screen() call was added to panic() in c7c3f05e341a ("panic: avoid deadlocks in re-entrant console drivers"), which partially inlined the bust_spinlocks(0); call. Long story short, I have no idea why the direct call to unblank_screen survived for so long (the infrastructure to do it properly existed for years), nor why it wasn't removed when the console_unblank() call was finally added. But it makes a ton more sense to finally do that than not - it's just better encapsulation to go through the console functions instead of doing a direct call, so let's dare. Plus it really does not make much sense to call the only unblank implementation there is twice, once without, and once with appropriate locking. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Xuezhi Zhang <zhangxuezhi1@coolpad.com> Cc: Yangxi Xiang <xyangxi5@gmail.com> Cc: nick black <dankamongmen@gmail.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com> Cc: Marco Elver <elver@google.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: David Gow <davidgow@google.com> Cc: tangmeng <tangmeng@uniontech.com> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/r/20220830145004.430545-1-daniel.vetter@ffwll.ch Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'linux-kselftest-kunit-5.20-rc1' of ↵Linus Torvalds2022-08-021-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest Pull KUnit updates from Shuah Khan: "This consists of several fixes and an important feature to discourage running KUnit tests on production systems. Running tests on a production system could leave the system in a bad state. Summary: - Add a new taint type, TAINT_TEST to signal that a test has been run. This should discourage people from running these tests on production systems, and to make it easier to tell if tests have been run accidentally (by loading the wrong configuration, etc) - Several documentation and tool enhancements and fixes" * tag 'linux-kselftest-kunit-5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (29 commits) Documentation: KUnit: Fix example with compilation error Documentation: kunit: Add CLI args for kunit_tool kcsan: test: Add a .kunitconfig to run KCSAN tests kunit: executor: Fix a memory leak on failure in kunit_filter_tests clk: explicitly disable CONFIG_UML_PCI_OVER_VIRTIO in .kunitconfig mmc: sdhci-of-aspeed: test: Use kunit_test_suite() macro nitro_enclaves: test: Use kunit_test_suite() macro thunderbolt: test: Use kunit_test_suite() macro kunit: flatten kunit_suite*** to kunit_suite** in .kunit_test_suites kunit: unify module and builtin suite definitions selftest: Taint kernel when test module loaded module: panic: Taint the kernel when selftest modules load Documentation: kunit: fix example run_kunit func to allow spaces in args Documentation: kunit: Cleanup run_wrapper, fix x-ref kunit: test.h: fix a kernel-doc markup kunit: tool: Enable virtio/PCI by default on UML kunit: tool: make --kunitconfig repeatable, blindly concat kunit: add coverage_uml.config to enable GCOV on UML kunit: tool: refactor internal kconfig handling, allow overriding kunit: tool: introduce --qemu_args ...
| * panic: Taint kernel if tests are runDavid Gow2022-07-011-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most in-kernel tests (such as KUnit tests) are not supposed to run on production systems: they may do deliberately illegal things to trigger errors, and have security implications (for example, KUnit assertions will often deliberately leak kernel addresses). Add a new taint type, TAINT_TEST to signal that a test has been run. This will be printed as 'N' (originally for kuNit, as every other sensible letter was taken.) This should discourage people from running these tests on production systems, and to make it easier to tell if tests have been run accidentally (by loading the wrong configuration, etc.) Acked-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: David Gow <davidgow@google.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
* | Merge branch 'rework/kthreads' into for-linusPetr Mladek2022-06-231-6/+0
|\ \
| * | Revert "printk: add functions to prefer direct printing"Petr Mladek2022-06-231-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 2bb2b7b57f81255c13f4395ea911d6bdc70c9fe2. The testing of 5.19 release candidates revealed missing synchronization between early and regular console functionality. It would be possible to start the console kthreads later as a workaround. But it is clear that console lock serialized console drivers between each other. It opens a big area of possible problems that were not considered by people involved in the development and review. printk() is crucial for debugging kernel issues and console output is very important part of it. The number of consoles is huge and a proper review would take some time. As a result it need to be reverted for 5.19. Link: https://lore.kernel.org/r/YrBdjVwBOVgLfHyb@alley Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20220623145157.21938-7-pmladek@suse.com
| * | Revert "printk: Wait for the global console lock when the system is going down"Petr Mladek2022-06-231-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit b87f02307d3cfbda768520f0687c51ca77e14fc3. The testing of 5.19 release candidates revealed missing synchronization between early and regular console functionality. It would be possible to start the console kthreads later as a workaround. But it is clear that console lock serialized console drivers between each other. It opens a big area of possible problems that were not considered by people involved in the development and review. printk() is crucial for debugging kernel issues and console output is very important part of it. The number of consoles is huge and a proper review would take some time. As a result it need to be reverted for 5.19. Link: https://lore.kernel.org/r/YrBdjVwBOVgLfHyb@alley Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20220623145157.21938-2-pmladek@suse.com
* | | Merge branch 'rework/kthreads' into for-linusPetr Mladek2022-06-171-0/+2
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| * printk: Wait for the global console lock when the system is going downPetr Mladek2022-06-151-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are reports that the console kthreads block the global console lock when the system is going down, for example, reboot, panic. First part of the solution was to block kthreads in these problematic system states so they stopped handling newly added messages. Second part of the solution is to wait when for the kthreads when they are actively printing. It solves the problem when a message was printed before the system entered the problematic state and the kthreads managed to step in. A busy waiting has to be used because panic() can be called in any context and in an unknown state of the scheduler. There must be a timeout because the kthread might get stuck or sleeping and never release the lock. The timeout 10s is an arbitrary value inspired by the softlockup timeout. Link: https://lore.kernel.org/r/20220610205038.GA3050413@paulmck-ThinkPad-P17-Gen-1 Link: https://lore.kernel.org/r/CAMdYzYpF4FNTBPZsEFeWRuEwSies36QM_As8osPWZSr2q-viEA@mail.gmail.com Signed-off-by: Petr Mladek <pmladek@suse.com> Tested-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/r/20220615162805.27962-3-pmladek@suse.com
* | Merge tag 'sysctl-5.19-rc1' of ↵Linus Torvalds2022-05-261-1/+25
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux Pull sysctl updates from Luis Chamberlain: "For two kernel releases now kernel/sysctl.c has been being cleaned up slowly, since the tables were grossly long, sprinkled with tons of #ifdefs and all this caused merge conflicts with one susbystem or another. This tree was put together to help try to avoid conflicts with these cleanups going on different trees at time. So nothing exciting on this pull request, just cleanups. Thanks a lot to the Uniontech and Huawei folks for doing some of this nasty work" * tag 'sysctl-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (28 commits) sched: Fix build warning without CONFIG_SYSCTL reboot: Fix build warning without CONFIG_SYSCTL kernel/kexec_core: move kexec_core sysctls into its own file sysctl: minor cleanup in new_dir() ftrace: fix building with SYSCTL=y but DYNAMIC_FTRACE=n fs/proc: Introduce list_for_each_table_entry for proc sysctl mm: fix unused variable kernel warning when SYSCTL=n latencytop: move sysctl to its own file ftrace: fix building with SYSCTL=n but DYNAMIC_FTRACE=y ftrace: Fix build warning ftrace: move sysctl_ftrace_enabled to ftrace.c kernel/do_mount_initrd: move real_root_dev sysctls to its own file kernel/delayacct: move delayacct sysctls to its own file kernel/acct: move acct sysctls to its own file kernel/panic: move panic sysctls to its own file kernel/lockdep: move lockdep sysctls to its own file mm: move page-writeback sysctls to their own file mm: move oom_kill sysctls to their own file kernel/reboot: move reboot sysctls to its own file sched: Move energy_aware sysctls to topology.c ...
| * kernel/panic: move panic sysctls to its own filetangmeng2022-04-061-1/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kernel/sysctl.c is a kitchen sink where everyone leaves their dirty dishes, this makes it very difficult to maintain. To help with this maintenance let's start by moving sysctls to places where they actually belong. The proc sysctl maintainers do not want to know what sysctl knobs you wish to add for your own piece of code, we just care about the core logic. All filesystem syctls now get reviewed by fs folks. This commit follows the commit of fs, move the oops_all_cpu_backtrace sysctl to its own file, kernel/panic.c. Signed-off-by: tangmeng <tangmeng@uniontech.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
* | Merge tag 'printk-for-5.19' of ↵Linus Torvalds2022-05-251-0/+4
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux Pull printk updates from Petr Mladek: - Offload writing printk() messages on consoles to per-console kthreads. It prevents soft-lockups when an extensive amount of messages is printed. It was observed, for example, during boot of large systems with a lot of peripherals like disks or network interfaces. It prevents live-lockups that were observed, for example, when messages about allocation failures were reported and a CPU handled consoles instead of reclaiming the memory. It was hard to solve even with rate limiting because it would need to take into account the amount of messages and the speed of all consoles. It is a must to have for real time. Otherwise, any printk() might break latency guarantees. The per-console kthreads allow to handle each console on its own speed. Slow consoles do not longer slow down faster ones. And printk() does not longer unpredictably slows down various code paths. There are situations when the kthreads are either not available or not reliable, for example, early boot, suspend, or panic. In these situations, printk() uses the legacy mode and tries to handle consoles immediately. - Add documentation for the printk index. * tag 'printk-for-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: printk, tracing: fix console tracepoint printk: remove @console_locked printk: extend console_lock for per-console locking printk: add kthread console printers printk: add functions to prefer direct printing printk: add pr_flush() printk: move buffer definitions into console_emit_next_record() caller printk: refactor and rework printing logic printk: add con_printk() macro for console details printk: call boot_delay_msec() in printk_delay() printk: get caller_id/timestamp after migration disable printk: wake waiters for safe and NMI contexts printk: wake up all waiters printk: add missing memory barrier to wake_up_klogd() printk: cpu sync always disable interrupts printk: rename cpulock functions printk/index: Printk index feature documentation MAINTAINERS: Add printk indexing maintainers on mention of printk_index
| * | printk: add functions to prefer direct printingJohn Ogness2022-04-221-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Once kthread printing is available, console printing will no longer occur in the context of the printk caller. However, there are some special contexts where it is desirable for the printk caller to directly print out kernel messages. Using pr_flush() to wait for threaded printers is only possible if the caller is in a sleepable context and the kthreads are active. That is not always the case. Introduce printk_prefer_direct_enter() and printk_prefer_direct_exit() functions to explicitly (and globally) activate/deactivate preferred direct console printing. The term "direct console printing" refers to printing to all enabled consoles from the context of the printk caller. The term "prefer" is used because this type of printing is only best effort. If the console is currently locked or other printers are already actively printing, the printk caller will need to rely on the other contexts to handle the printing. This preferred direct printing is how all printing has been handled until now (unless it was explicitly deferred). When kthread printing is introduced, there may be some unanticipated problems due to kthreads being unable to flush important messages. In order to minimize such risks, preferred direct printing is activated for the primary important messages when the system experiences general types of major errors. These are: - emergency reboot/shutdown - cpu and rcu stalls - hard and soft lockups - hung tasks - warn - sysrq Note that since kthread printing does not yet exist, no behavior changes result from this commit. This is only implementing the counter and marking the various places where preferred direct printing is active. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> # for RCU Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20220421212250.565456-13-john.ogness@linutronix.de
* | | randstruct: Reorganize Kconfigs and attribute macrosKees Cook2022-05-081-1/+1
| |/ |/| | | | | | | | | | | | | | | | | | | | | In preparation for Clang supporting randstruct, reorganize the Kconfigs, move the attribute macros, and generalize the feature to be named CONFIG_RANDSTRUCT for on/off, CONFIG_RANDSTRUCT_FULL for the full randomization mode, and CONFIG_RANDSTRUCT_PERFORMANCE for the cache-line sized mode. Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220503205503.3054173-4-keescook@chromium.org
* | panic: move panic_print before kmsg dumpersGuilherme G. Piccoli2022-03-231-4/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The panic_print setting allows users to collect more information in a panic event, like memory stats, tasks, CPUs backtraces, etc. This is an interesting debug mechanism, but currently the print event happens *after* kmsg_dump(), meaning that pstore, for example, cannot collect a dmesg with the panic_print extra information. This patch changes that in 2 steps: (a) The panic_print setting allows to replay the existing kernel log buffer to the console (bit 5), besides the extra information dump. This functionality makes sense only at the end of the panic() function. So, we hereby allow to distinguish the two situations by a new boolean parameter in the function panic_print_sys_info(). (b) With the above change, we can safely call panic_print_sys_info() before kmsg_dump(), allowing to dump the extra information when using pstore or other kmsg dumpers. The additional messages from panic_print could overwrite the oldest messages when the buffer is full. The only reasonable solution is to use a large enough log buffer, hence we added an advice into the kernel parameters documentation about that. Link: https://lkml.kernel.org/r/20220214141308.841525-1-gpiccoli@igalia.com Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Acked-by: Baoquan He <bhe@redhat.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Feng Tang <feng.tang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | panic: add option to dump all CPUs backtraces in panic_printGuilherme G. Piccoli2022-03-231-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the "panic_print" parameter/sysctl allows some interesting debug information to be printed during a panic event. This is useful for example in cases the user cannot kdump due to resource limits, or if the user collects panic logs in a serial output (or pstore) and prefers a fast reboot instead of a kdump. Happens that currently there's no way to see all CPUs backtraces in a panic using "panic_print" on architectures that support that. We do have "oops_all_cpu_backtrace" sysctl, but although partially overlapping in the functionality, they are orthogonal in nature: "panic_print" is a panic tuning (and we have panics without oopses, like direct calls to panic() or maybe other paths that don't go through oops_enter() function), and the original purpose of "oops_all_cpu_backtrace" is to provide more information on oopses for cases in which the users desire to continue running the kernel even after an oops, i.e., used in non-panic scenarios. So, we hereby introduce an additional bit for "panic_print" to allow dumping the CPUs backtraces during a panic event. Link: https://lkml.kernel.org/r/20211109202848.610874-3-gpiccoli@igalia.com Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Reviewed-by: Feng Tang <feng.tang@intel.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Samuel Iglesias Gonsalvez <siglesias@igalia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | panic: unset panic_on_warn inside panic()Tiezhu Yang2022-03-231-9/+11
|/ | | | | | | | | | | | | | | | | | | | | | | In the current code, the following three places need to unset panic_on_warn before calling panic() to avoid recursive panics: kernel/kcsan/report.c: print_report() kernel/sched/core.c: __schedule_bug() mm/kfence/report.c: kfence_report_error() In order to avoid copy-pasting "panic_on_warn = 0" all over the places, it is better to move it inside panic() and then remove it from the other places. Link: https://lkml.kernel.org/r/1644324666-15947-4-git-send-email-yangtiezhu@loongson.cn Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Reviewed-by: Marco Elver <elver@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Xuefeng Li <lixuefeng@loongson.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* panic: remove oops_idSebastian Andrzej Siewior2022-01-201-18/+1
| | | | | | | | | | | | | | | | | | | | | | | | | The oops id has been added as part of the end of trace marker for the kerneloops.org project. The id is used to automatically identify duplicate submissions of the same report. Identical looking reports with different a id can be considered as the same oops occurred again. The early initialisation of the oops_id can create a warning if the random core is not yet fully initialized. On PREEMPT_RT it is problematic if the id is initialized on demand from non preemptible context. The kernel oops project is not available since 2017. Remove the oops_id and use 0 in the output in case parser rely on it. Link: https://bugs.debian.org/953172 Link: https://lkml.kernel.org/r/Ybdi16aP2NEugWHq@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* panic: use error_report_end tracepoint on warningsMarco Elver2022-01-201-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | Introduce the error detector "warning" to the error_report event and use the error_report_end tracepoint at the end of a warning report. This allows in-kernel tests but also userspace to more easily determine if a warning occurred without polling kernel logs. [akpm@linux-foundation.org: add comma to enum list, per Andy] Link: https://lkml.kernel.org/r/20211115085630.1756817-1-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Alexander Potapenko <glider@google.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Wei Liu <wei.liu@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: John Ogness <john.ogness@linutronix.de> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Alexander Popov <alex.popov@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'rework/printk_safe-removal' into for-linusPetr Mladek2021-08-301-3/+0
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| * printk: remove safe buffersJohn Ogness2021-07-261-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With @logbuf_lock removed, the high level printk functions for storing messages are lockless. Messages can be stored from any context, so there is no need for the NMI and safe buffers anymore. Remove the NMI and safe buffers. Although the safe buffers are removed, the NMI and safe context tracking is still in place. In these contexts, store the message immediately but still use irq_work to defer the console printing. Since printk recursion tracking is in place, safe context tracking for most of printk is not needed. Remove it. Only safe context tracking relating to the console and console_owner locks is left in place. This is because the console and console_owner locks are needed for the actual printing. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210715193359.25946-4-john.ogness@linutronix.de
* | kernel.h: split out panic and oops helpersAndy Shevchenko2021-07-011-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kernel.h is being used as a dump for all kinds of stuff for a long time. Here is the attempt to start cleaning it up by splitting out panic and oops helpers. There are several purposes of doing this: - dropping dependency in bug.h - dropping a loop by moving out panic_notifier.h - unload kernel.h from something which has its own domain At the same time convert users tree-wide to use new headers, although for the time being include new header back to kernel.h to avoid twisted indirected includes for existing users. [akpm@linux-foundation.org: thread_info.h needs limits.h] [andriy.shevchenko@linux.intel.com: ia64 fix] Link: https://lkml.kernel.org/r/20210520130557.55277-1-andriy.shevchenko@linux.intel.com Link: https://lkml.kernel.org/r/20210511074137.33666-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Co-developed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Corey Minyard <cminyard@mvista.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Wei Liu <wei.liu@kernel.org> Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Sebastian Reichel <sre@kernel.org> Acked-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Stephen Boyd <sboyd@kernel.org> Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Acked-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* panic: don't dump stack twice on warnChristophe Leroy2020-11-141-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before commit 3f388f28639f ("panic: dump registers on panic_on_warn"), __warn() was calling show_regs() when regs was not NULL, and show_stack() otherwise. After that commit, show_stack() is called regardless of whether show_regs() has been called or not, leading to duplicated Call Trace: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at arch/powerpc/mm/nohash/8xx.c:186 mmu_mark_initmem_nx+0x24/0x94 CPU: 0 PID: 1 Comm: swapper Not tainted 5.10.0-rc2-s3k-dev-01375-gf46ec0d3ecbd-dirty #4092 NIP: c00128b4 LR: c0010228 CTR: 00000000 REGS: c9023e40 TRAP: 0700 Not tainted (5.10.0-rc2-s3k-dev-01375-gf46ec0d3ecbd-dirty) MSR: 00029032 <EE,ME,IR,DR,RI> CR: 24000424 XER: 00000000 GPR00: c0010228 c9023ef8 c2100000 0074c000 ffffffff 00000000 c2151000 c07b3880 GPR08: ff000900 0074c000 c8000000 c33b53a8 24000822 00000000 c0003a20 00000000 GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 GPR24: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00800000 NIP [c00128b4] mmu_mark_initmem_nx+0x24/0x94 LR [c0010228] free_initmem+0x20/0x58 Call Trace: free_initmem+0x20/0x58 kernel_init+0x1c/0x114 ret_from_kernel_thread+0x14/0x1c Instruction dump: 7d291850 7d234b78 4e800020 9421ffe0 7c0802a6 bfc10018 3fe0c060 3bff0000 3fff4080 3bffffff 90010024 57ff0010 <0fe00000> 392001cd 7c3e0b78 953e0008 CPU: 0 PID: 1 Comm: swapper Not tainted 5.10.0-rc2-s3k-dev-01375-gf46ec0d3ecbd-dirty #4092 Call Trace: __warn+0x8c/0xd8 (unreliable) report_bug+0x11c/0x154 program_check_exception+0x1dc/0x6e0 ret_from_except_full+0x0/0x4 --- interrupt: 700 at mmu_mark_initmem_nx+0x24/0x94 LR = free_initmem+0x20/0x58 free_initmem+0x20/0x58 kernel_init+0x1c/0x114 ret_from_kernel_thread+0x14/0x1c ---[ end trace 31702cd2a9570752 ]--- Only call show_stack() when regs is NULL. Fixes: 3f388f28639f ("panic: dump registers on panic_on_warn") Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Link: https://lkml.kernel.org/r/e8c055458b080707f1bc1a98ff8bea79d0cec445.1604748361.git.christophe.leroy@csgroup.eu Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* panic: dump registers on panic_on_warnAlexey Kardashevskiy2020-10-161-6/+6
| | | | | | | | | | | | | | | | | | | | | | | Currently we print stack and registers for ordinary warnings but we do not for panic_on_warn which looks as oversight - panic() will reboot the machine but won't print registers. This moves printing of registers and modules earlier. This does not move the stack dumping as panic() dumps it. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Douglas Anderson <dianders@chromium.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Rafael Aquini <aquini@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Link: https://lkml.kernel.org/r/20200804095054.68724-1-aik@ozlabs.ru Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* panic: make print_oops_end_marker() staticYue Hu2020-08-121-1/+1
| | | | | | | | | | | Since print_oops_end_marker() is not used externally, also remove it in kernel.h at the same time. Signed-off-by: Yue Hu <huyue2@yulong.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Kees Cook <keescook@chromium.org> Link: http://lkml.kernel.org/r/20200724011516.12756-1-zbestahu@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/panic.c: make oops_may_print() return boolTiezhu Yang2020-08-121-1/+1
| | | | | | | | | | | | The return value of oops_may_print() is true or false, so change its type to reflect that. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Xuefeng Li <lixuefeng@loongson.cn> Link: http://lkml.kernel.org/r/1591103358-32087-1-git-send-email-yangtiezhu@loongson.cn Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* bug: Annotate WARN/BUG/stackfail as noinstr safeThomas Gleixner2020-06-111-1/+3
| | | | | | | | | | | | | | | | Warnings, bugs and stack protection fails from noinstr sections, e.g. low level and early entry code, are likely to be fatal. Mark them as "safe" to be invoked from noinstr protected code to avoid annotating all usage sites. Getting the information out is important. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200505134100.376598577@linutronix.de
* panic: add sysctl to dump all CPUs backtraces on oops eventGuilherme G. Piccoli2020-06-081-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Usually when the kernel reaches an oops condition, it's a point of no return; in case not enough debug information is available in the kernel splat, one of the last resorts would be to collect a kernel crash dump and analyze it. The problem with this approach is that in order to collect the dump, a panic is required (to kexec-load the crash kernel). When in an environment of multiple virtual machines, users may prefer to try living with the oops, at least until being able to properly shutdown their VMs / finish their important tasks. This patch implements a way to collect a bit more debug details when an oops event is reached, by printing all the CPUs backtraces through the usage of NMIs (on architectures that support that). The sysctl added (and documented) here was called "oops_all_cpu_backtrace", and when set will (as the name suggests) dump all CPUs backtraces. Far from ideal, this may be the last option though for users that for some reason cannot panic on oops. Most of times oopses are clear enough to indicate the kernel portion that must be investigated, but in virtual environments it's possible to observe hypervisor/KVM issues that could lead to oopses shown in other guests CPUs (like virtual APIC crashes). This patch hence aims to help debug such complex issues without resorting to kdump. Signed-off-by: Guilherme G. Piccoli <gpiccoli@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Matthew Wilcox <willy@infradead.org> Link: http://lkml.kernel.org/r/20200327224116.21030-1-gpiccoli@canonical.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel: add panic_on_taintRafael Aquini2020-06-081-0/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Analogously to the introduction of panic_on_warn, this patch introduces a kernel option named panic_on_taint in order to provide a simple and generic way to stop execution and catch a coredump when the kernel gets tainted by any given flag. This is useful for debugging sessions as it avoids having to rebuild the kernel to explicitly add calls to panic() into the code sites that introduce the taint flags of interest. For instance, if one is interested in proceeding with a post-mortem analysis at the point a given code path is hitting a bad page (i.e. unaccount_page_cache_page(), or slab_bug()), a coredump can be collected by rebooting the kernel with 'panic_on_taint=0x20' amended to the command line. Another, perhaps less frequent, use for this option would be as a means for assuring a security policy case where only a subset of taints, or no single taint (in paranoid mode), is allowed for the running system. The optional switch 'nousertaint' is handy in this particular scenario, as it will avoid userspace induced crashes by writes to sysctl interface /proc/sys/kernel/tainted causing false positive hits for such policies. [akpm@linux-foundation.org: tweak kernel-parameters.txt wording] Suggested-by: Qian Cai <cai@lca.pw> Signed-off-by: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Bunk <bunk@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Laura Abbott <labbott@redhat.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: Takashi Iwai <tiwai@suse.de> Link: http://lkml.kernel.org/r/20200515175502.146720-1-aquini@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* locking/refcount: Remove unused 'refcount_error_report()' functionWill Deacon2019-11-251-11/+0
| | | | | | | | | | | | | | | | 'refcount_error_report()' has no callers. Remove it. Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Kees Cook <keescook@chromium.org> Tested-by: Hanjun Guo <guohanjun@huawei.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20191121115902.2551-10-will@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* panic: ensure preemption is disabled during panic()Will Deacon2019-10-071-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Calling 'panic()' on a kernel with CONFIG_PREEMPT=y can leave the calling CPU in an infinite loop, but with interrupts and preemption enabled. From this state, userspace can continue to be scheduled, despite the system being "dead" as far as the kernel is concerned. This is easily reproducible on arm64 when booting with "nosmp" on the command line; a couple of shell scripts print out a periodic "Ping" message whilst another triggers a crash by writing to /proc/sysrq-trigger: | sysrq: Trigger a crash | Kernel panic - not syncing: sysrq triggered crash | CPU: 0 PID: 1 Comm: init Not tainted 5.2.15 #1 | Hardware name: linux,dummy-virt (DT) | Call trace: | dump_backtrace+0x0/0x148 | show_stack+0x14/0x20 | dump_stack+0xa0/0xc4 | panic+0x140/0x32c | sysrq_handle_reboot+0x0/0x20 | __handle_sysrq+0x124/0x190 | write_sysrq_trigger+0x64/0x88 | proc_reg_write+0x60/0xa8 | __vfs_write+0x18/0x40 | vfs_write+0xa4/0x1b8 | ksys_write+0x64/0xf0 | __arm64_sys_write+0x14/0x20 | el0_svc_common.constprop.0+0xb0/0x168 | el0_svc_handler+0x28/0x78 | el0_svc+0x8/0xc | Kernel Offset: disabled | CPU features: 0x0002,24002004 | Memory Limit: none | ---[ end Kernel panic - not syncing: sysrq triggered crash ]--- | Ping 2! | Ping 1! | Ping 1! | Ping 2! The issue can also be triggered on x86 kernels if CONFIG_SMP=n, otherwise local interrupts are disabled in 'smp_send_stop()'. Disable preemption in 'panic()' before re-enabling interrupts. Link: http://lkml.kernel.org/r/20191002123538.22609-1-will@kernel.org Link: https://lore.kernel.org/r/BX1W47JXPMR8.58IYW53H6M5N@dragonstone Signed-off-by: Will Deacon <will@kernel.org> Reported-by: Xogium <contact@xogium.me> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Feng Tang <feng.tang@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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