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* ftrace: Add ftrace_lookup_symbols functionJiri Olsa2022-05-101-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | Adding ftrace_lookup_symbols function that resolves array of symbols with single pass over kallsyms. The user provides array of string pointers with count and pointer to allocated array for resolved values. int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs) It iterates all kallsyms symbols and tries to loop up each in provided symbols array with bsearch. The symbols array needs to be sorted by name for this reason. We also check each symbol to pass ftrace_location, because this API will be used for fprobe symbols resolving. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20220510122616.2652285-3-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* kallsyms: Make kallsyms_on_each_symbol generally availableJiri Olsa2022-05-101-2/+0
| | | | | | | | | | | | | | Making kallsyms_on_each_symbol generally available, so it can be used outside CONFIG_LIVEPATCH option in following changes. Rather than adding another ifdef option let's make the function generally available (when CONFIG_KALLSYMS option is defined). Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20220510122616.2652285-2-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* kallsyms: Skip the name search for empty stringJiri Olsa2022-03-171-0/+4
| | | | | | | | | | | When kallsyms_lookup_name is called with empty string, it will do futile search for it through all the symbols. Skipping the search for empty string. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220316122419.933957-3-jolsa@kernel.org
* Merge tag 'livepatching-for-5.17' of ↵Linus Torvalds2022-01-161-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching Pull livepatching updates from Petr Mladek: - Correctly handle kobjects when a livepatch init fails - Avoid CPU hogging when searching for many livepatched symbols - Add livepatch API page into documentation * tag 'livepatching-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching: livepatch: Avoid CPU hogging with cond_resched livepatch: Fix missing unlock on error in klp_enable_patch() livepatch: Fix kobject refcount bug on klp_init_patch_early failure path Documentation: livepatch: Add livepatch API page
| * livepatch: Avoid CPU hogging with cond_reschedDavid Vernet2022-01-071-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When initializing a 'struct klp_object' in klp_init_object_loaded(), and performing relocations in klp_resolve_symbols(), klp_find_object_symbol() is invoked to look up the address of a symbol in an already-loaded module (or vmlinux). This, in turn, calls kallsyms_on_each_symbol() or module_kallsyms_on_each_symbol() to find the address of the symbol that is being patched. It turns out that symbol lookups often take up the most CPU time when enabling and disabling a patch, and may hog the CPU and cause other tasks on that CPU's runqueue to starve -- even in paths where interrupts are enabled. For example, under certain workloads, enabling a KLP patch with many objects or functions may cause ksoftirqd to be starved, and thus for interrupts to be backlogged and delayed. This may end up causing TCP retransmits on the host where the KLP patch is being applied, and in general, may cause any interrupts serviced by softirqd to be delayed while the patch is being applied. So as to ensure that kallsyms_on_each_symbol() does not end up hogging the CPU, this patch adds a call to cond_resched() in kallsyms_on_each_symbol() and module_kallsyms_on_each_symbol(), which are invoked when doing a symbol lookup in vmlinux and a module respectively. Without this patch, if a live-patch is applied on a 36-core Intel host with heavy TCP traffic, a ~10x spike is observed in TCP retransmits while the patch is being applied. Additionally, collecting sched events with perf indicates that ksoftirqd is awakened ~1.3 seconds before it's eventually scheduled. With the patch, no increase in TCP retransmit events is observed, and ksoftirqd is scheduled shortly after it's awakened. Signed-off-by: David Vernet <void@manifault.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Song Liu <song@kernel.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20211229215646.830451-1-void@manifault.com
* | kallsyms: strip LTO suffixes from static functionsNick Desaulniers2021-10-041-13/+33
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | Similar to: commit 8b8e6b5d3b01 ("kallsyms: strip ThinLTO hashes from static functions") It's very common for compilers to modify the symbol name for static functions as part of optimizing transformations. That makes hooking static functions (that weren't inlined or DCE'd) with kprobes difficult. LLVM has yet another name mangling scheme used by thin LTO. Combine handling of the various schemes by truncating after the first '.'. Strip off these suffixes so that we can continue to hook such static functions. Clang releases prior to clang-13 would use '$' instead of '.' Link: https://reviews.llvm.org/rGc6e5c4654bd5045fe22a1a52779e48e2038a404c Reported-by: KE.LI(Lieke) <like1@oppo.com> Suggested-by: Nathan Chancellor <nathan@kernel.org> Suggested-by: Padmanabha Srinivasaiah <treasure4paddy@gmail.com> Suggested-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20211004162936.21961-1-ndesaulniers@google.com
* module: add printk formats to add module build ID to stacktracesStephen Boyd2021-07-081-20/+84
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's make kernel stacktraces easier to identify by including the build ID[1] of a module if the stacktrace is printing a symbol from a module. This makes it simpler for developers to locate a kernel module's full debuginfo for a particular stacktrace. Combined with scripts/decode_stracktrace.sh, a developer can download the matching debuginfo from a debuginfod[2] server and find the exact file and line number for the functions plus offsets in a stacktrace that match the module. This is especially useful for pstore crash debugging where the kernel crashes are recorded in something like console-ramoops and the recovery kernel/modules are different or the debuginfo doesn't exist on the device due to space concerns (the debuginfo can be too large for space limited devices). Originally, I put this on the %pS format, but that was quickly rejected given that %pS is used in other places such as ftrace where build IDs aren't meaningful. There was some discussions on the list to put every module build ID into the "Modules linked in:" section of the stacktrace message but that quickly becomes very hard to read once you have more than three or four modules linked in. It also provides too much information when we don't expect each module to be traversed in a stacktrace. Having the build ID for modules that aren't important just makes things messy. Splitting it to multiple lines for each module quickly explodes the number of lines printed in an oops too, possibly wrapping the warning off the console. And finally, trying to stash away each module used in a callstack to provide the ID of each symbol printed is cumbersome and would require changes to each architecture to stash away modules and return their build IDs once unwinding has completed. Instead, we opt for the simpler approach of introducing new printk formats '%pS[R]b' for "pointer symbolic backtrace with module build ID" and '%pBb' for "pointer backtrace with module build ID" and then updating the few places in the architecture layer where the stacktrace is printed to use this new format. Before: Call trace: lkdtm_WARNING+0x28/0x30 [lkdtm] direct_entry+0x16c/0x1b4 [lkdtm] full_proxy_write+0x74/0xa4 vfs_write+0xec/0x2e8 After: Call trace: lkdtm_WARNING+0x28/0x30 [lkdtm 6c2215028606bda50de823490723dc4bc5bf46f9] direct_entry+0x16c/0x1b4 [lkdtm 6c2215028606bda50de823490723dc4bc5bf46f9] full_proxy_write+0x74/0xa4 vfs_write+0xec/0x2e8 [akpm@linux-foundation.org: fix build with CONFIG_MODULES=n, tweak code layout] [rdunlap@infradead.org: fix build when CONFIG_MODULES is not set] Link: https://lkml.kernel.org/r/20210513171510.20328-1-rdunlap@infradead.org [akpm@linux-foundation.org: make kallsyms_lookup_buildid() static] [cuibixuan@huawei.com: fix build error when CONFIG_SYSFS is disabled] Link: https://lkml.kernel.org/r/20210525105049.34804-1-cuibixuan@huawei.com Link: https://lkml.kernel.org/r/20210511003845.2429846-6-swboyd@chromium.org Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1] Link: https://sourceware.org/elfutils/Debuginfod.html [2] Signed-off-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Bixuan Cui <cuibixuan@huawei.com> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Jessica Yu <jeyu@kernel.org> Cc: Evan Green <evgreen@chromium.org> Cc: Hsin-Yi Wang <hsinyi@chromium.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Matthew Wilcox <willy@infradead.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Young <dyoung@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Sasha Levin <sashal@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kallsyms: strip ThinLTO hashes from static functionsSami Tolvanen2021-04-081-5/+50
| | | | | | | | | | | | | | With CONFIG_CFI_CLANG and ThinLTO, Clang appends a hash to the names of all static functions not marked __used. This can break userspace tools that don't expect the function name to change, so strip out the hash from the output. Suggested-by: Jack Pham <jackp@codeaurora.org> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210408182843.1754385-8-samitolvanen@google.com
* kallsyms: only build {,module_}kallsyms_on_each_symbol when requiredChristoph Hellwig2021-02-081-0/+2
| | | | | | | | | | kallsyms_on_each_symbol and module_kallsyms_on_each_symbol are only used by the livepatching code, so don't build them if livepatching is not enabled. Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jessica Yu <jeyu@kernel.org>
* kallsyms: refactor {,module_}kallsyms_on_each_symbolChristoph Hellwig2021-02-081-1/+5
| | | | | | | | | | | | | | | Require an explicit call to module_kallsyms_on_each_symbol to look for symbols in modules instead of the call from kallsyms_on_each_symbol, and acquire module_mutex inside of module_kallsyms_on_each_symbol instead of leaving that up to the caller. Note that this slightly changes the behavior for the livepatch code in that the symbols from vmlinux are not iterated anymore if objname is set, but that actually is the desired behavior in this case. Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jessica Yu <jeyu@kernel.org>
* treewide: Convert macro and uses of __section(foo) to __section("foo")Joe Perches2020-10-251-2/+2
| | | | | | | | | | | | | | | | | | | | Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva2020-08-231-2/+2
| | | | | | | | | | Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
* Merge tag 'v5.8-rc7' into perf/core, to pick up fixesIngo Molnar2020-07-281-6/+11
|\ | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * kallsyms: Refactor kallsyms_show_value() to take credKees Cook2020-07-081-6/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to perform future tests against the cred saved during open(), switch kallsyms_show_value() to operate on a cred, and have all current callers pass current_cred(). This makes it very obvious where callers are checking the wrong credential in their "read" contexts. These will be fixed in the coming patches. Additionally switch return value to bool, since it is always used as a direct permission check, not a 0-on-success, negative-on-error style function return. Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
* | ftrace: Add symbols for ftrace trampolinesAdrian Hunter2020-06-151-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Symbols are needed for tools to describe instruction addresses. Pages allocated for ftrace's purposes need symbols to be created for them. Add such symbols to be visible via /proc/kallsyms. Example on x86 with CONFIG_DYNAMIC_FTRACE=y # echo function > /sys/kernel/debug/tracing/current_tracer # cat /proc/kallsyms | grep '\[__builtin__ftrace\]' ffffffffc0238000 t ftrace_trampoline [__builtin__ftrace] Note: This patch adds "__builtin__ftrace" as a module name in /proc/kallsyms for symbols for pages allocated for ftrace's purposes, even though "__builtin__ftrace" is not a module. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200512121922.8997-7-adrian.hunter@intel.com
* | kprobes: Add symbols for kprobe insn pagesAdrian Hunter2020-06-151-4/+33
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Symbols are needed for tools to describe instruction addresses. Pages allocated for kprobe's purposes need symbols to be created for them. Add such symbols to be visible via /proc/kallsyms. Note: kprobe insn pages are not used if ftrace is configured. To see the effect of this patch, the kernel must be configured with: # CONFIG_FUNCTION_TRACER is not set CONFIG_KPROBES=y and for optimised kprobes: CONFIG_OPTPROBES=y Example on x86: # perf probe __schedule Added new event: probe:__schedule (on __schedule) # cat /proc/kallsyms | grep '\[__builtin__kprobes\]' ffffffffc00d4000 t kprobe_insn_page [__builtin__kprobes] ffffffffc00d6000 t kprobe_optinsn_page [__builtin__kprobes] Note: This patch adds "__builtin__kprobes" as a module name in /proc/kallsyms for symbols for pages allocated for kprobes' purposes, even though "__builtin__kprobes" is not a module. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lkml.kernel.org/r/20200528080058.20230-1-adrian.hunter@intel.com
* kallsyms: unexport kallsyms_lookup_name() and kallsyms_on_each_symbol()Will Deacon2020-04-071-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | kallsyms_lookup_name() and kallsyms_on_each_symbol() are exported to modules despite having no in-tree users and being wide open to abuse by out-of-tree modules that can use them as a method to invoke arbitrary non-exported kernel functions. Unexport kallsyms_lookup_name() and kallsyms_on_each_symbol(). Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Quentin Perret <qperret@google.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Petr Mladek <pmladek@suse.com> Cc: Joe Lawrence <joe.lawrence@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: http://lkml.kernel.org/r/20200221114404.14641-4-will@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'kbuild-v5.6-2' of ↵Linus Torvalds2020-02-091-2/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull more Kbuild updates from Masahiro Yamada: - fix randconfig to generate a sane .config - rename hostprogs-y / always to hostprogs / always-y, which are more natual syntax. - optimize scripts/kallsyms - fix yes2modconfig and mod2yesconfig - make multiple directory targets ('make foo/ bar/') work * tag 'kbuild-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: make multiple directory targets work kconfig: Invalidate all symbols after changing to y or m. kallsyms: fix type of kallsyms_token_table[] scripts/kallsyms: change table to store (strcut sym_entry *) scripts/kallsyms: rename local variables in read_symbol() kbuild: rename hostprogs-y/always to hostprogs/always-y kbuild: fix the document to use extra-y for vmlinux.lds kconfig: fix broken dependency in randconfig-generated .config
| * kallsyms: fix type of kallsyms_token_table[]Masahiro Yamada2020-02-051-2/+3
| | | | | | | | | | | | | | | | kallsyms_token_table[] only contains ASCII characters. It should be char instead of u8. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
* | proc: convert everything to "struct proc_ops"Alexey Dobriyan2020-02-041-6/+6
|/ | | | | | | | | | | | | | | | | | | | | | | The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in seq_file.h. Conversion rule is: llseek => proc_lseek unlocked_ioctl => proc_ioctl xxx => proc_xxx delete ".owner = THIS_MODULE" line [akpm@linux-foundation.org: fix drivers/isdn/capi/kcapi_proc.c] [sfr@canb.auug.org.au: fix kernel/sched/psi.c] Link: http://lkml.kernel.org/r/20200122180545.36222f50@canb.auug.org.au Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kallsyms: Don't let kallsyms_lookup_size_offset() fail on retrieving the ↵Marc Zyngier2019-08-271-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | first symbol An arm64 kernel configured with CONFIG_KPROBES=y CONFIG_KALLSYMS=y # CONFIG_KALLSYMS_ALL is not set CONFIG_KALLSYMS_BASE_RELATIVE=y reports the following kprobe failure: [ 0.032677] kprobes: failed to populate blacklist: -22 [ 0.033376] Please take care of using kprobes. It appears that kprobe fails to retrieve the symbol at address 0xffff000010081000, despite this symbol being in System.map: ffff000010081000 T __exception_text_start This symbol is part of the first group of aliases in the kallsyms_offsets array (symbol names generated using ugly hacks in scripts/kallsyms.c): kallsyms_offsets: .long 0x1000 // do_undefinstr .long 0x1000 // efi_header_end .long 0x1000 // _stext .long 0x1000 // __exception_text_start .long 0x12b0 // do_cp15instr Looking at the implementation of get_symbol_pos(), it returns the lowest index for aliasing symbols. In this case, it return 0. But kallsyms_lookup_size_offset() considers 0 as a failure, which is obviously wrong (there is definitely a valid symbol living there). In turn, the kprobe blacklisting stops abruptly, hence the original error. A CONFIG_KALLSYMS_ALL kernel wouldn't fail as there is always some random symbols at the beginning of this array, which are never looked up via kallsyms_lookup_size_offset. Fix it by considering that get_symbol_pos() is always successful (which is consistent with the other uses of this function). Fixes: ffc5089196446 ("[PATCH] Create kallsyms_lookup_size_offset()") Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
* treewide: Add SPDX license identifier for missed filesThomas Gleixner2019-05-211-0/+1
| | | | | | | | | | | | | | | | | Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* bpf: Add module name [bpf] to ksymbols for bpf programsSong Liu2019-01-211-1/+1
| | | | | | | | | | | | | | | | | | With this patch, /proc/kallsyms will show BPF programs as <addr> t bpf_prog_<tag>_<name> [bpf] Signed-off-by: Song Liu <songliubraving@fb.com> Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: kernel-team@fb.com Cc: netdev@vger.kernel.org Link: http://lkml.kernel.org/r/20190117161521.1341602-10-songliubraving@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* kallsyms: reduce size a little on 64-bitJan Beulich2018-09-101-2/+2
| | | | | | | | Both kallsyms_num_syms and kallsyms_markers[] don't really need to use unsigned long as their (base) types; unsigned int fully suffices. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
* kallsyms, x86: Export addresses of PTI entry trampolinesAlexander Shishkin2018-08-141-1/+27
| | | | | | | | | | | | | | | | | | | | Currently, the addresses of PTI entry trampolines are not exported to user space. Kernel profiling tools need these addresses to identify the kernel code, so add a symbol and address for each CPU's PTI entry trampoline. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86@kernel.org Link: http://lkml.kernel.org/r/1528289651-4113-3-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* kallsyms: Simplify update_iter_mod()Adrian Hunter2018-08-141-14/+11
| | | | | | | | | | | | | | | | | | | | | | | The logic in update_iter_mod() is overcomplicated and gets worse every time another get_ksymbol_* function is added. In preparation for adding another get_ksymbol_* function, simplify logic in update_iter_mod(). Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Tested-by: (ftrace changes only) Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86@kernel.org Link: http://lkml.kernel.org/r/1528289651-4113-2-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2018-02-011-46/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk Pull printk updates from Petr Mladek: - Add a console_msg_format command line option: The value "default" keeps the old "[time stamp] text\n" format. The value "syslog" allows to see the syslog-like "<log level>[timestamp] text" format. This feature was requested by people doing regression tests, for example, 0day robot. They want to have both filtered and full logs at hands. - Reduce the risk of softlockup: Pass the console owner in a busy loop. This is a new approach to the old problem. It was first proposed by Steven Rostedt on Kernel Summit 2017. It marks a context in which the console_lock owner calls console drivers and could not sleep. On the other side, printk() callers could detect this state and use a busy wait instead of a simple console_trylock(). Finally, the console_lock owner checks if there is a busy waiter at the end of the special context and eventually passes the console_lock to the waiter. The hand-off works surprisingly well and helps in many situations. Well, there is still a possibility of the softlockup, for example, when the flood of messages stops and the last owner still has too much to flush. There is increasing number of people having problems with printk-related softlockups. We might eventually need to get better solution. Anyway, this looks like a good start and promising direction. - Do not allow to schedule in console_unlock() called from printk(): This reverts an older controversial commit. The reschedule helped to avoid softlockups. But it also slowed down the console output. This patch is obsoleted by the new console waiter logic described above. In fact, the reschedule made the hand-off less effective. - Deprecate "%pf" and "%pF" format specifier: It was needed on ia64, ppc64 and parisc64 to dereference function descriptors and show the real function address. It is done transparently by "%ps" and "pS" format specifier now. Sergey Senozhatsky found that all the function descriptors were in a special elf section and could be easily detected. - Remove printk_symbol() API: It has been obsoleted by "%pS" format specifier, and this change helped to remove few continuous lines and a less intuitive old API. - Remove redundant memsets: Sergey removed unnecessary memset when processing printk.devkmsg command line option. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: (27 commits) printk: drop redundant devkmsg_log_str memsets printk: Never set console_may_schedule in console_trylock() printk: Hide console waiter logic into helpers printk: Add console owner and waiter logic to load balance console writes kallsyms: remove print_symbol() function checkpatch: add pF/pf deprecation warning symbol lookup: introduce dereference_symbol_descriptor() parisc64: Add .opd based function descriptor dereference powerpc64: Add .opd based function descriptor dereference ia64: Add .opd based function descriptor dereference sections: split dereference_function_descriptor() openrisc: Fix conflicting types for _exext and _stext lib: do not use print_symbol() irq debug: do not use print_symbol() sysfs: do not use print_symbol() drivers: do not use print_symbol() x86: do not use print_symbol() unicore32: do not use print_symbol() sh: do not use print_symbol() mn10300: do not use print_symbol() ...
| * Merge branch 'for-4.16-print-symbol' into for-4.16Petr Mladek2018-01-221-11/+0
| |\
| | * kallsyms: remove print_symbol() functionSergey Senozhatsky2018-01-161-11/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No more print_symbol()/__print_symbol() users left, remove these symbols. It was a very old API that encouraged people use continuous lines. It had been obsoleted by %pS format specifier in a normal printk() call. Link: http://lkml.kernel.org/r/20180105102538.GC471@jagdpanzerIV Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Salter <msalter@redhat.com> Cc: Tony Luck <tony.luck@intel.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Borislav Petkov <bp@alien8.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: LKML <linux-kernel@vger.kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-ia64@vger.kernel.org Cc: linux-am33-list@redhat.com Cc: linux-sh@vger.kernel.org Cc: linux-edac@vger.kernel.org Cc: x86@kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Suggested-by: Joe Perches <joe@perches.com> [pmladek@suse.com: updated commit message] Signed-off-by: Petr Mladek <pmladek@suse.com>
| * | symbol lookup: introduce dereference_symbol_descriptor()Sergey Senozhatsky2018-01-091-35/+0
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | dereference_symbol_descriptor() invokes appropriate ARCH specific function descriptor dereference callbacks: - dereference_kernel_function_descriptor() if the pointer is a kernel symbol; - dereference_module_function_descriptor() if the pointer is a module symbol. This is the last step needed to make '%pS/%ps' smart enough to handle function descriptor dereference on affected ARCHs and to retire '%pF/%pf'. To refresh it: Some architectures (ia64, ppc64, parisc64) use an indirect pointer for C function pointers - the function pointer points to a function descriptor and we need to dereference it to get the actual function pointer. Function descriptors live in .opd elf section and all affected ARCHs (ia64, ppc64, parisc64) handle it properly for kernel and modules. So we, technically, can decide if the dereference is needed by simply looking at the pointer: if it belongs to .opd section then we need to dereference it. The kernel and modules have their own .opd sections, obviously, that's why we need to split dereference_function_descriptor() and use separate kernel and module dereference arch callbacks. Link: http://lkml.kernel.org/r/20171206043649.GB15885@jagdpanzerIV Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: James Bottomley <jejb@parisc-linux.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jessica Yu <jeyu@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-ia64@vger.kernel.org Cc: linux-parisc@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Tested-by: Tony Luck <tony.luck@intel.com> #ia64 Tested-by: Santosh Sivaraj <santosh@fossix.org> #powerpc Tested-by: Helge Deller <deller@gmx.de> #parisc64 Signed-off-by: Petr Mladek <pmladek@suse.com>
* / kallsyms: take advantage of the new '%px' formatLinus Torvalds2017-11-291-4/+4
|/ | | | | | | | | | The conditional kallsym hex printing used a special fixed-width '%lx' output (KALLSYM_FMT) in preparation for the hashing of %p, but that series ended up adding a %px specifier to help with the conversions. Use it, and avoid the "print pointer as an unsigned long" code. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'trace-v4.15' of ↵Linus Torvalds2017-11-171-6/+37
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from - allow module init functions to be traced - clean up some unused or not used by config events (saves space) - clean up of trace histogram code - add support for preempt and interrupt enabled/disable events - other various clean ups * tag 'trace-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (30 commits) tracing, thermal: Hide cpu cooling trace events when not in use tracing, thermal: Hide devfreq trace events when not in use ftrace: Kill FTRACE_OPS_FL_PER_CPU perf/ftrace: Small cleanup perf/ftrace: Fix function trace events perf/ftrace: Revert ("perf/ftrace: Fix double traces of perf on ftrace:function") tracing, dma-buf: Remove unused trace event dma_fence_annotate_wait_on tracing, memcg, vmscan: Hide trace events when not in use tracing/xen: Hide events that are not used when X86_PAE is not defined tracing: mark trace_test_buffer as __maybe_unused printk: Remove superfluous memory barriers from printk_safe ftrace: Clear hashes of stale ips of init memory tracing: Add support for preempt and irq enable/disable events tracing: Prepare to add preempt and irq trace events ftrace/kallsyms: Have /proc/kallsyms show saved mod init functions ftrace: Add freeing algorithm to free ftrace_mod_maps ftrace: Save module init functions kallsyms symbols for tracing ftrace: Allow module init functions to be traced ftrace: Add a ftrace_free_mem() function for modules to use tracing: Reimplement log2 ...
| * ftrace/kallsyms: Have /proc/kallsyms show saved mod init functionsSteven Rostedt (VMware)2017-10-051-6/+32
| | | | | | | | | | | | | | | | | | | | | | | | If a module is loaded while tracing is enabled, then there's a possibility that the module init functions were traced. These functions have their name and address stored by ftrace such that it can translate the function address that is written into the buffer into a human readable function name. As userspace tools may be doing the same, they need a way to map function names to their address as well. This is done through reading /proc/kallsyms. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * ftrace: Save module init functions kallsyms symbols for tracingSteven Rostedt (VMware)2017-10-051-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If function tracing is active when the module init functions are freed, then store them to be referenced by kallsyms. As module init functions can now be traced on module load, they were useless: ># echo ':mod:snd_seq' > set_ftrace_filter ># echo function > current_tracer ># modprobe snd_seq ># cat trace # tracer: function # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | modprobe-2786 [000] .... 3189.037874: 0xffffffffa0860000 <-do_one_initcall modprobe-2786 [000] .... 3189.037876: 0xffffffffa086004d <-0xffffffffa086000f modprobe-2786 [000] .... 3189.037876: 0xffffffffa086010d <-0xffffffffa0860018 modprobe-2786 [000] .... 3189.037877: 0xffffffffa086011a <-0xffffffffa0860021 modprobe-2786 [000] .... 3189.037877: 0xffffffffa0860080 <-0xffffffffa086002a modprobe-2786 [000] .... 3189.039523: 0xffffffffa0860400 <-0xffffffffa0860033 modprobe-2786 [000] .... 3189.039523: 0xffffffffa086038a <-0xffffffffa086041c modprobe-2786 [000] .... 3189.039591: 0xffffffffa086038a <-0xffffffffa0860436 modprobe-2786 [000] .... 3189.039657: 0xffffffffa086038a <-0xffffffffa0860450 modprobe-2786 [000] .... 3189.039719: 0xffffffffa0860127 <-0xffffffffa086003c modprobe-2786 [000] .... 3189.039742: snd_seq_create_kernel_client <-0xffffffffa08601f6 When the output is shown, the kallsyms for the module init functions have already been freed, and the output of the trace can not convert them to their function names. Now this looks like this: # tracer: function # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | modprobe-2463 [002] .... 174.243237: alsa_seq_init <-do_one_initcall modprobe-2463 [002] .... 174.243239: client_init_data <-alsa_seq_init modprobe-2463 [002] .... 174.243240: snd_sequencer_memory_init <-alsa_seq_init modprobe-2463 [002] .... 174.243240: snd_seq_queues_init <-alsa_seq_init modprobe-2463 [002] .... 174.243240: snd_sequencer_device_init <-alsa_seq_init modprobe-2463 [002] .... 174.244860: snd_seq_info_init <-alsa_seq_init modprobe-2463 [002] .... 174.244861: create_info_entry <-snd_seq_info_init modprobe-2463 [002] .... 174.244936: create_info_entry <-snd_seq_info_init modprobe-2463 [002] .... 174.245003: create_info_entry <-snd_seq_info_init modprobe-2463 [002] .... 174.245072: snd_seq_system_client_init <-alsa_seq_init modprobe-2463 [002] .... 174.245094: snd_seq_create_kernel_client <-snd_seq_system_client_init Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* | /proc/module: use the same logic as /proc/kallsyms for address exposureLinus Torvalds2017-11-121-7/+1
| | | | | | | | | | | | | | | | | | The (alleged) users of the module addresses are the same: kernel profiling. So just expose the same helper and format macros, and unify the logic. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | stop using '%pK' for /proc/kallsyms pointer valuesLinus Torvalds2017-11-081-2/+47
|/ | | | | | | | | | | | | | | | Not only is it annoying to have one single flag for all pointers, as if that was a global choice and all kernel pointers are the same, but %pK can't get the 'access' vs 'open' time check right anyway. So make the /proc/kallsyms pointer value code use logic specific to that particular file. We do continue to honor kptr_restrict, but the default (which is unrestricted) is changed to instead take expected users into account, and restrict access by default. Right now the only actual expected user is kernel profiling, which has a separate sysctl flag for kernel profile access. There may be others. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/kallsyms.c: replace all_var with IS_ENABLED(CONFIG_KALLSYMS_ALL)Masahiro Yamada2017-07-101-8/+2
| | | | | | | | | | | | | 'all_var' looks like a variable, but is actually a macro. Use IS_ENABLED(CONFIG_KALLSYMS_ALL) for clarification. Link: http://lkml.kernel.org/r/1497577591-3434-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* bpf: make jited programs visible in tracesDaniel Borkmann2017-02-171-12/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Long standing issue with JITed programs is that stack traces from function tracing check whether a given address is kernel code through {__,}kernel_text_address(), which checks for code in core kernel, modules and dynamically allocated ftrace trampolines. But what is still missing is BPF JITed programs (interpreted programs are not an issue as __bpf_prog_run() will be attributed to them), thus when a stack trace is triggered, the code walking the stack won't see any of the JITed ones. The same for address correlation done from user space via reading /proc/kallsyms. This is read by tools like perf, but the latter is also useful for permanent live tracing with eBPF itself in combination with stack maps when other eBPF types are part of the callchain. See offwaketime example on dumping stack from a map. This work tries to tackle that issue by making the addresses and symbols known to the kernel. The lookup from *kernel_text_address() is implemented through a latched RB tree that can be read under RCU in fast-path that is also shared for symbol/size/offset lookup for a specific given address in kallsyms. The slow-path iteration through all symbols in the seq file done via RCU list, which holds a tiny fraction of all exported ksyms, usually below 0.1 percent. Function symbols are exported as bpf_prog_<tag>, in order to aide debugging and attribution. This facility is currently enabled for root-only when bpf_jit_kallsyms is set to 1, and disabled if hardening is active in any mode. The rationale behind this is that still a lot of systems ship with world read permissions on kallsyms thus addresses should not get suddenly exposed for them. If that situation gets much better in future, we always have the option to change the default on this. Likewise, unprivileged programs are not allowed to add entries there either, but that is less of a concern as most such programs types relevant in this context are for root-only anyway. If enabled, call graphs and stack traces will then show a correct attribution; one example is illustrated below, where the trace is now visible in tooling such as perf script --kallsyms=/proc/kallsyms and friends. Before: 7fff8166889d bpf_clone_redirect+0x80007f0020ed (/lib/modules/4.9.0-rc8+/build/vmlinux) f5d80 __sendmsg_nocancel+0xffff006451f1a007 (/usr/lib64/libc-2.18.so) After: 7fff816688b7 bpf_clone_redirect+0x80007f002107 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fffa0575728 bpf_prog_33c45a467c9e061a+0x8000600020fb (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fffa07ef1fc cls_bpf_classify+0x8000600020dc (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff81678b68 tc_classify+0x80007f002078 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164d40b __netif_receive_skb_core+0x80007f0025fb (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164d718 __netif_receive_skb+0x80007f002018 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164e565 process_backlog+0x80007f002095 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164dc71 net_rx_action+0x80007f002231 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff81767461 __softirqentry_text_start+0x80007f0020d1 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff817658ac do_softirq_own_stack+0x80007f00201c (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff810a2c20 do_softirq+0x80007f002050 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff810a2cb5 __local_bh_enable_ip+0x80007f002085 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8168d452 ip_finish_output2+0x80007f002152 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8168ea3d ip_finish_output+0x80007f00217d (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8168f2af ip_output+0x80007f00203f (/lib/modules/4.9.0-rc8+/build/vmlinux) [...] 7fff81005854 do_syscall_64+0x80007f002054 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff817649eb return_from_SYSCALL_64+0x80007f002000 (/lib/modules/4.9.0-rc8+/build/vmlinux) f5d80 __sendmsg_nocancel+0xffff01c484812007 (/usr/lib64/libc-2.18.so) Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
* kallsyms: add support for relative offsets in kallsyms address tableArd Biesheuvel2016-03-151-9/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Similar to how relative extables are implemented, it is possible to emit the kallsyms table in such a way that it contains offsets relative to some anchor point in the kernel image rather than absolute addresses. On 64-bit architectures, it cuts the size of the kallsyms address table in half, since offsets between kernel symbols can typically be expressed in 32 bits. This saves several hundreds of kilobytes of permanent .rodata on average. In addition, the kallsyms address table is no longer subject to dynamic relocation when CONFIG_RELOCATABLE is in effect, so the relocation work done after decompression now doesn't have to do relocation updates for all these values. This saves up to 24 bytes (i.e., the size of a ELF64 RELA relocation table entry) per value, which easily adds up to a couple of megabytes of uncompressed __init data on ppc64 or arm64. Even if these relocation entries typically compress well, the combined size reduction of 2.8 MB uncompressed for a ppc64_defconfig build (of which 2.4 MB is __init data) results in a ~500 KB space saving in the compressed image. Since it is useful for some architectures (like x86) to retain the ability to emit absolute values as well, this patch also adds support for capturing both absolute and relative values when KALLSYMS_ABSOLUTE_PERCPU is in effect, by emitting absolute per-cpu addresses as positive 32-bit values, and addresses relative to the lowest encountered relative symbol as negative values, which are subtracted from the runtime address of this base symbol to produce the actual address. Support for the above is enabled by default for all architectures except IA-64 and Tile-GX, whose symbols are too far apart to capture in this manner. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Kees Cook <keescook@chromium.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Ingo Molnar <mingo@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/kallsyms.c: use __seq_open_private()Rob Jones2014-10-141-9/+2
| | | | | | | | | | Reduce boilerplate code by using __seq_open_private() instead of seq_open() in kallsyms_open(). Signed-off-by: Rob Jones <rob.jones@codethink.co.uk> Cc: Gideon Israel Dsouza <gidisrael@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/kallsyms.c: fix %pB when there's no symbol at the addressNamhyung Kim2014-08-081-1/+1
| | | | | | | | | | | | | | | | | | | | | __sprint_symbol() should restore original address when kallsyms_lookup() failed to find a symbol. It's reported when dumpstack shows an address in a dynamically allocated trampoline for ftrace. [ 1314.612287] [<ffffffff81700312>] dump_stack+0x45/0x56 [ 1314.612290] [<ffffffff8125f5b0>] ? meminfo_proc_open+0x30/0x30 [ 1314.612293] [<ffffffffa080a494>] kpatch_ftrace_handler+0x14/0xf0 [kpatch] [ 1314.612306] [<ffffffffa00160c4>] 0xffffffffa00160c3 You can see a difference in the hex address - c4 and c3. Fix it. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Reported-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel: use macros from compiler.h instead of __attribute__((...))Gideon Israel Dsouza2014-04-071-5/+6
| | | | | | | | | | | | | To increase compiler portability there is <linux/compiler.h> which provides convenience macros for various gcc constructs. Eg: __weak for __attribute__((weak)). I've replaced all instances of gcc attributes with the right macro in the kernel subsystem. Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel: kallsyms: memory override issue, need check destination buffer lengthChen Gang2013-04-151-8/+18
| | | | | | | | | | | | | | | | | | | We don't export any symbols > 128 characters, but if we did then kallsyms_expand_symbol() would overflow the buffer handed to it. So we need check destination buffer length when copying. the related test: if we define an EXPORT function which name more than 128. will panic when call kallsyms_lookup_name by init_kprobes on booting. after check the length (provide this patch), it is ok. Implementaion: add additional destination buffer length parameter (maxlen) if uncompressed string is too long (>= maxlen), it will be truncated. not check the parameters whether valid, since it is a static function. Signed-off-by: Chen Gang <gang.chen@asianux.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* vsprintf: fix %ps on non symbols when using kallsymsStephen Boyd2012-05-291-8/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using %ps in a printk format will sometimes fail silently and print the empty string if the address passed in does not match a symbol that kallsyms knows about. But using %pS will fall back to printing the full address if kallsyms can't find the symbol. Make %ps act the same as %pS by falling back to printing the address. While we're here also make %ps print the module that a symbol comes from so that it matches what %pS already does. Take this simple function for example (in a module): static void test_printk(void) { int test; pr_info("with pS: %pS\n", &test); pr_info("with ps: %ps\n", &test); } Before this patch: with pS: 0xdff7df44 with ps: After this patch: with pS: 0xdff7df44 with ps: 0xdff7df44 Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds2011-03-251-3/+41
|\ | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futex: Fix WARN_ON() test for UP WARN_ON_SMP(): Allow use in if() statements on UP x86, dumpstack: Use %pB format specifier for stack trace vsprintf: Introduce %pB format specifier lockdep: Remove unused 'factor' variable from lockdep_stats_show()
| * vsprintf: Introduce %pB format specifierNamhyung Kim2011-03-241-3/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The %pB format specifier is for stack backtrace. Its handler sprint_backtrace() does symbol lookup using (address-1) to ensure the address will not point outside of the function. If there is a tail-call to the function marked "noreturn", gcc optimized out the code after the call then causes saved return address points outside of the function (i.e. the start of the next function), so pollutes call trace somewhat. This patch adds the %pB printk mechanism that allows architecture call-trace printout functions to improve backtrace printouts. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-arch@vger.kernel.org LKML-Reference: <1300934550-21394-1-git-send-email-namhyung@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge branch 'for-linus' of ↵Linus Torvalds2011-03-231-2/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: deal with races in /proc/*/{syscall,stack,personality} proc: enable writing to /proc/pid/mem proc: make check_mem_permission() return an mm_struct on success proc: hold cred_guard_mutex in check_mem_permission() proc: disable mem_write after exec mm: implement access_remote_vm mm: factor out main logic of access_process_vm mm: use mm_struct to resolve gate vma's in __get_user_pages mm: arch: rename in_gate_area_no_task to in_gate_area_no_mm mm: arch: make in_gate_area take an mm_struct instead of a task_struct mm: arch: make get_gate_vma take an mm_struct instead of a task_struct x86: mark associated mm when running a task in 32 bit compatibility mode x86: add context tag to mark mm when running a task in 32-bit compatibility mode auxv: require the target to be tracable (or yourself) close race in /proc/*/environ report errors in /proc/*/*map* sanely pagemap: close races with suid execve make sessionid permissions in /proc/*/task/* match those in /proc/* fix leaks in path_lookupat() Fix up trivial conflicts in fs/proc/base.c
| * | mm: arch: rename in_gate_area_no_task to in_gate_area_no_mmStephen Wilson2011-03-231-2/+2
| |/ | | | | | | | | | | | | | | | | | | | | | | | | Now that gate vma's are referenced with respect to a particular mm and not a particular task it only makes sense to propagate the change to this predicate as well. Signed-off-by: Stephen Wilson <wilsons@start.ca> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* / printk: use %pK for /proc/kallsyms and /proc/modulesKees Cook2011-03-221-6/+4
|/ | | | | | | | | | | | | | | | | | | | | | | In an effort to reduce kernel address leaks that might be used to help target kernel privilege escalation exploits, this patch uses %pK when displaying addresses in /proc/kallsyms, /proc/modules, and /sys/module/*/sections/*. Note that this changes %x to %p, so some legitimately 0 values in /proc/kallsyms would have changed from 00000000 to "(null)". To avoid this, "(null)" is not used when using the "K" format. Anything that was already successfully parsing "(null)" in addition to full hex digits should have no problem with this change. (Thanks to Joe Perches for the suggestion.) Due to the %x to %p, "void *" casts are needed since these addresses are already "unsigned long" everywhere internally, due to their starting life as ELF section offsets. Signed-off-by: Kees Cook <kees.cook@canonical.com> Cc: Eugene Teo <eugene@redhat.com> Cc: Dan Rosenberg <drosenberg@vsecurity.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Revert "kernel: make /proc/kallsyms mode 400 to reduce ease of attacking"Linus Torvalds2010-11-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 59365d136d205cc20fe666ca7f89b1c5001b0d5a. It turns out that this can break certain existing user land setups. Quoth Sarah Sharp: "On Wednesday, I updated my branch to commit 460781b from linus' tree, and my box would not boot. klogd segfaulted, which stalled the whole system. At first I thought it actually hung the box, but it continued booting after 5 minutes, and I was able to log in. It dropped back to the text console instead of the graphical bootup display for that period of time. dmesg surprisingly still works. I've bisected the problem down to this commit (commit 59365d136d205cc20fe666ca7f89b1c5001b0d5a) The box is running klogd 1.5.5ubuntu3 (from Jaunty). Yes, I know that's old. I read the bit in the commit about changing the permissions of kallsyms after boot, but if I can't boot that doesn't help." So let's just keep the old default, and encourage distributions to do the "chmod -r /proc/kallsyms" in their bootup scripts. This is not worth a kernel option to change default behavior, since it's so easily done in user space. Reported-and-bisected-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Cc: Marcus Meissner <meissner@suse.de> Cc: Tejun Heo <tj@kernel.org> Cc: Eugene Teo <eugeneteo@kernel.org> Cc: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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