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* sched/wait: assert the wait_queue_head lock is held in __wake_up_commonChristoph Hellwig2018-08-221-0/+2
| | | | | | | | | | | | | | | | | | | | Better ensure we actually hold the lock using lockdep than just commenting on it. Due to the various exported _locked interfaces it is far too easy to get the locking wrong. Link: http://lkml.kernel.org/r/20171214152344.6880-4-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel: tracepoints: add support for relative referencesArd Biesheuvel2018-08-221-23/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To avoid the need for relocating absolute references to tracepoint structures at boot time when running relocatable kernels (which may take a disproportionate amount of space), add the option to emit these tables as relative references instead. Link: http://lkml.kernel.org/r/20180704083651.24360-7-ard.biesheuvel@linaro.org Acked-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morris <james.morris@microsoft.com> Cc: James Morris <jmorris@namei.org> Cc: Jessica Yu <jeyu@kernel.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Nicolas Pitre <nico@linaro.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Russell King <linux@armlinux.org.uk> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* init: allow initcall tables to be emitted using relative referencesArd Biesheuvel2018-08-221-7/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow the initcall tables to be emitted using relative references that are only half the size on 64-bit architectures and don't require fixups at runtime on relocatable kernels. Link: http://lkml.kernel.org/r/20180704083651.24360-5-ard.biesheuvel@linaro.org Acked-by: James Morris <james.morris@microsoft.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Petr Mladek <pmladek@suse.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morris <jmorris@namei.org> Cc: Jessica Yu <jeyu@kernel.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Nicolas Pitre <nico@linaro.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Russell King <linux@armlinux.org.uk> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* module: use relative references for __ksymtab entriesArd Biesheuvel2018-08-221-6/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | An ordinary arm64 defconfig build has ~64 KB worth of __ksymtab entries, each consisting of two 64-bit fields containing absolute references, to the symbol itself and to a char array containing its name, respectively. When we build the same configuration with KASLR enabled, we end up with an additional ~192 KB of relocations in the .init section, i.e., one 24 byte entry for each absolute reference, which all need to be processed at boot time. Given how the struct kernel_symbol that describes each entry is completely local to module.c (except for the references emitted by EXPORT_SYMBOL() itself), we can easily modify it to contain two 32-bit relative references instead. This reduces the size of the __ksymtab section by 50% for all 64-bit architectures, and gets rid of the runtime relocations entirely for architectures implementing KASLR, either via standard PIE linking (arm64) or using custom host tools (x86). Note that the binary search involving __ksymtab contents relies on each section being sorted by symbol name. This is implemented based on the input section names, not the names in the ksymtab entries, so this patch does not interfere with that. Given that the use of place-relative relocations requires support both in the toolchain and in the module loader, we cannot enable this feature for all architectures. So make it dependent on whether CONFIG_HAVE_ARCH_PREL32_RELOCATIONS is defined. Link: http://lkml.kernel.org/r/20180704083651.24360-4-ard.biesheuvel@linaro.org Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Jessica Yu <jeyu@kernel.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Will Deacon <will.deacon@arm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morris <james.morris@microsoft.com> Cc: James Morris <jmorris@namei.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Nicolas Pitre <nico@linaro.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Russell King <linux@armlinux.org.uk> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/hung_task.c: allow to set checking interval separately from timeoutDmitry Vyukov2018-08-223-2/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently task hung checking interval is equal to timeout, as the result hung is detected anywhere between timeout and 2*timeout. This is fine for most interactive environments, but this hurts automated testing setups (syzbot). In an automated setup we need to strictly order CPU lockup < RCU stall < workqueue lockup < task hung < silent loss, so that RCU stall is not detected as task hung and task hung is not detected as silent machine loss. The large variance in task hung detection timeout requires setting silent machine loss timeout to a very large value (e.g. if task hung is 3 mins, then silent loss need to be set to ~7 mins). The additional 3 minutes significantly reduce testing efficiency because usually we crash kernel within a minute, and this can add hours to bug localization process as it needs to do dozens of tests. Allow setting checking interval separately from timeout. This allows to set timeout to, say, 3 minutes, but checking interval to 10 secs. The interval is controlled via a new hung_task_check_interval_secs sysctl, similar to the existing hung_task_timeout_secs sysctl. The default value of 0 results in the current behavior: checking interval is equal to timeout. [akpm@linux-foundation.org: update hung_task_timeout_max's comment] Link: http://lkml.kernel.org/r/20180611111004.203513-1-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> 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/crash_core.c: print timestamp using time64_tArnd Bergmann2018-08-221-1/+1
| | | | | | | | | | | | | | | | | The get_seconds() call returns a 32-bit timestamp on some architectures, and will overflow in the future. The newer ktime_get_real_seconds() always returns a 64-bit timestamp that does not suffer from this problem. Link: http://lkml.kernel.org/r/20180618150329.941903-1-arnd@arndb.de Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Petr Tesarik <ptesarik@suse.cz> Cc: Marc-Andr Lureau <marcandre.lureau@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* userns: use irqsave variant of refcount_dec_and_lock()Anna-Maria Gleixner2018-08-221-4/+1
| | | | | | | | | | | | | | | | | The irqsave variant of refcount_dec_and_lock handles irqsave/restore when taking/releasing the spin lock. With this variant the call of local_irq_save/restore is no longer required. [bigeasy@linutronix.de: s@atomic_dec_and_lock@refcount_dec_and_lock@g] Link: http://lkml.kernel.org/r/20180703200141.28415-7-bigeasy@linutronix.de Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* userns: use refcount_t for reference counting instead atomic_tSebastian Andrzej Siewior2018-08-221-4/+4
| | | | | | | | | | | | | | | | | refcount_t type and corresponding API should be used instead of atomic_t wh en the variable is used as a reference counter. This avoids accidental refcounter overflows that might lead to use-after-free situations. Link: http://lkml.kernel.org/r/20180703200141.28415-6-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Suggested-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc/kcore: add vmcoreinfo note to /proc/kcoreOmar Sandoval2018-08-221-2/+2
| | | | | | | | | | | | | | | | The vmcoreinfo information is useful for runtime debugging tools, not just for crash dumps. A lot of this information can be determined by other means, but this is much more convenient, and it only adds a page at most to the file. Link: http://lkml.kernel.org/r/fddbcd08eed76344863303878b12de1c1e2a04b6.1531953780.git.osandov@fb.com Signed-off-by: Omar Sandoval <osandov@fb.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Bhupesh Sharma <bhsharma@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: James Morse <james.morse@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* crash_core: use VMCOREINFO_SYMBOL_ARRAY() for swapper_pg_dirOmar Sandoval2018-08-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is preparation for allowing CRASH_CORE to be enabled for any architecture. swapper_pg_dir is always either an array or a macro expanding to NULL. In the latter case, VMCOREINFO_SYMBOL() won't work, as it tries to take the address of the given symbol: #define VMCOREINFO_SYMBOL(name) \ vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)&name) Instead, use VMCOREINFO_SYMBOL_ARRAY(), which uses the value: #define VMCOREINFO_SYMBOL_ARRAY(name) \ vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)name) This is the same thing for the array case but isn't an error for the macro case. Link: http://lkml.kernel.org/r/c05f9781ec204f40fc96f95086e7b6de6a3eb2c3.1532563124.git.osandov@fb.com Signed-off-by: Omar Sandoval <osandov@fb.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Bhupesh Sharma <bhsharma@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: James Morse <james.morse@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: zero out the vma in vma_init()Andrew Morton2018-08-221-1/+2
| | | | | | | | | | | | | | Rather than in vm_area_alloc(). To ensure that the various oddball stack-based vmas are in a good state. Some of the callers were zeroing them out, others were not. Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'trace-v4.19' of ↵Linus Torvalds2018-08-2039-492/+566
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: - Restructure of lockdep and latency tracers This is the biggest change. Joel Fernandes restructured the hooks from irqs and preemption disabling and enabling. He got rid of a lot of the preprocessor #ifdef mess that they caused. He turned both lockdep and the latency tracers to use trace events inserted in the preempt/irqs disabling paths. But unfortunately, these started to cause issues in corner cases. Thus, parts of the code was reverted back to where lockdep and the latency tracers just get called directly (without using the trace events). But because the original change cleaned up the code very nicely we kept that, as well as the trace events for preempt and irqs disabling, but they are limited to not being called in NMIs. - Have trace events use SRCU for "rcu idle" calls. This was required for the preempt/irqs off trace events. But it also had to not allow them to be called in NMI context. Waiting till Paul makes an NMI safe SRCU API. - New notrace SRCU API to allow trace events to use SRCU. - Addition of mcount-nop option support - SPDX headers replacing GPL templates. - Various other fixes and clean ups. - Some fixes are marked for stable, but were not fully tested before the merge window opened. * tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits) tracing: Fix SPDX format headers to use C++ style comments tracing: Add SPDX License format tags to tracing files tracing: Add SPDX License format to bpf_trace.c blktrace: Add SPDX License format header s390/ftrace: Add -mfentry and -mnop-mcount support tracing: Add -mcount-nop option support tracing: Avoid calling cc-option -mrecord-mcount for every Makefile tracing: Handle CC_FLAGS_FTRACE more accurately Uprobe: Additional argument arch_uprobe to uprobe_write_opcode() Uprobes: Simplify uprobe_register() body tracepoints: Free early tracepoints after RCU is initialized uprobes: Use synchronize_rcu() not synchronize_sched() tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister() ftrace: Remove unused pointer ftrace_swapper_pid tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage" tracing/irqsoff: Handle preempt_count for different configs tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage" tracing: irqsoff: Account for additional preempt_disable trace: Use rcu_dereference_raw for hooks from trace-event subsystem tracing/kprobes: Fix within_notrace_func() to check only notrace functions ...
| * tracing: Fix SPDX format headers to use C++ style commentsSteven Rostedt (VMware)2018-08-168-8/+8
| | | | | | | | | | | | | | | | | | | | The Linux kernel adopted the SPDX License format headers to ease license compliance management, and uses the C++ '//' style comments for the SPDX header tags. Some files in the tracing directory used the C style /* */ comments for them. To be consistent across all files, replace the /* */ C style SPDX tags with the C++ // SPDX tags. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Add SPDX License format tags to tracing filesSteven Rostedt (VMware)2018-08-1620-102/+20
| | | | | | | | | | | | Add the SPDX License header to ease license compliance management. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Add SPDX License format to bpf_trace.cSteven Rostedt (VMware)2018-08-161-4/+1
| | | | | | | | | | | | | | | | Add the SPDX License header to ease license compliance management. Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * blktrace: Add SPDX License format headerSteven Rostedt (VMware)2018-08-161-13/+1
| | | | | | | | | | | | | | Add the SPDX License header to ease license compliance management. Acked-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Add -mcount-nop option supportVasily Gorbik2018-08-152-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | -mcount-nop gcc option generates the calls to the profiling functions as nops which allows to avoid patching mcount jump with NOP instructions initially. -mcount-nop gcc option will be activated if platform selects HAVE_NOP_MCOUNT and gcc actually supports it. In addition to that CC_USING_NOP_MCOUNT is defined and could be used by architectures to adapt ftrace patching behavior. Link: http://lkml.kernel.org/r/patch-3.thread-aa7b8d.git-e02ed2dc082b.your-ad-here.call-01533557518-ext-9465@work.hours Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * Uprobe: Additional argument arch_uprobe to uprobe_write_opcode()Ravi Bangoria2018-08-131-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | Add addition argument 'arch_uprobe' to uprobe_write_opcode(). We need this in later set of patches. Link: http://lkml.kernel.org/r/20180809041856.1547-3-ravi.bangoria@linux.ibm.com Reviewed-by: Song Liu <songliubraving@fb.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * Uprobes: Simplify uprobe_register() bodyRavi Bangoria2018-08-131-33/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | Simplify uprobe_register() function body and let __uprobe_register() handle everything. Also move dependency functions around to avoid build failures. Link: http://lkml.kernel.org/r/20180809041856.1547-2-ravi.bangoria@linux.ibm.com Reviewed-by: Song Liu <songliubraving@fb.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracepoints: Free early tracepoints after RCU is initializedSteven Rostedt (VMware)2018-08-101-0/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When enabling trace events via the kernel command line, I hit this warning: WARNING: CPU: 0 PID: 13 at kernel/rcu/srcutree.c:236 check_init_srcu_struct+0xe/0x61 Modules linked in: CPU: 0 PID: 13 Comm: watchdog/0 Not tainted 4.18.0-rc6-test+ #6 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014 RIP: 0010:check_init_srcu_struct+0xe/0x61 Code: 48 c7 c6 ec 8a 65 b4 e8 ff 79 fe ff 48 89 df 31 f6 e8 f2 fa ff ff 5a 5b 41 5c 5d c3 0f 1f 44 00 00 83 3d 68 94 b8 01 01 75 02 <0f> 0b 48 8b 87 f0 0a 00 00 a8 03 74 45 55 48 89 e5 41 55 41 54 4c RSP: 0000:ffff96eb9ea03e68 EFLAGS: 00010246 RAX: ffff96eb962b5b01 RBX: ffffffffb4a87420 RCX: 0000000000000001 RDX: ffffffffb3107969 RSI: ffff96eb962b5b40 RDI: ffffffffb4a87420 RBP: ffff96eb9ea03eb0 R08: ffffabbd00cd7f48 R09: 0000000000000000 R10: ffff96eb9ea03e68 R11: ffffffffb4a6eec0 R12: ffff96eb962b5b40 R13: ffff96eb9ea03ef8 R14: ffffffffb3107969 R15: ffffffffb3107948 FS: 0000000000000000(0000) GS:ffff96eb9ea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff96eb13ab2000 CR3: 0000000192a1e001 CR4: 00000000001606f0 Call Trace: <IRQ> ? __call_srcu+0x2d/0x290 ? rcu_process_callbacks+0x26e/0x448 ? allocate_probes+0x2b/0x2b call_srcu+0x13/0x15 rcu_free_old_probes+0x1f/0x21 rcu_process_callbacks+0x2ed/0x448 __do_softirq+0x172/0x336 irq_exit+0x62/0xb2 smp_apic_timer_interrupt+0x161/0x19e apic_timer_interrupt+0xf/0x20 </IRQ> The problem is that the enabling of trace events before RCU is set up will cause SRCU to give this warning. To avoid this, add a list to store probes that need to be freed till after RCU is initialized, and then free them then. Link: http://lkml.kernel.org/r/20180810113554.1df28050@gandalf.local.home Link: http://lkml.kernel.org/r/20180810123517.5e9714ad@gandalf.local.home Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Fixes: e6753f23d961d ("tracepoint: Make rcuidle tracepoint callers use SRCU") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * uprobes: Use synchronize_rcu() not synchronize_sched()Steven Rostedt (VMware)2018-08-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While debugging another bug, I was looking at all the synchronize*() functions being used in kernel/trace, and noticed that trace_uprobes was using synchronize_sched(), with a comment to synchronize with {u,ret}_probe_trace_func(). When looking at those functions, the data is protected with "rcu_read_lock()" and not with "rcu_read_lock_sched()". This is using the wrong synchronize_*() function. Link: http://lkml.kernel.org/r/20180809160553.469e1e32@gandalf.local.home Cc: stable@vger.kernel.org Fixes: 70ed91c6ec7f8 ("tracing/uprobes: Support ftrace_event_file base multibuffer") Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Fix synchronizing to event changes with ↵Steven Rostedt (VMware)2018-08-104-14/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tracepoint_synchronize_unregister() Now that some trace events can be protected by srcu_read_lock(tracepoint_srcu), we need to make sure all locations that depend on this are also protected. There were many places that did a synchronize_sched() thinking that it was enough to protect againts access to trace events. This use to be the case, but now that we use SRCU for _rcuidle() trace events, they may not be protected by synchronize_sched(), as they may be called in paths that RCU is not watching for preempt disable. Fixes: e6753f23d961d ("tracepoint: Make rcuidle tracepoint callers use SRCU") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * ftrace: Remove unused pointer ftrace_swapper_pidColin Ian King2018-08-101-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pointer ftrace_swapper_pid is defined but is never used hence it is redundant and can be removed. The use of this variable was removed in commit 345ddcc882d8 ("ftrace: Have set_ftrace_pid use the bitmap like events do"). Cleans up clang warning: warning: 'ftrace_swapper_pid' defined but not used [-Wunused-const-variable=] Link: http://lkml.kernel.org/r/20180809125609.13142-1-colin.king@canonical.com Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: More reverting of "tracing: Centralize preemptirq tracepoints and ↵Steven Rostedt (VMware)2018-08-103-50/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | unify their usage" Joel Fernandes created a nice patch that cleaned up the duplicate hooks used by lockdep and irqsoff latency tracer. It made both use tracepoints. But the latency tracer is triggering warnings when using tracepoints to call into the latency tracer's routines. Mainly, they can be called from NMI context. If that happens, then the SRCU may not work properly because on some architectures, SRCU is not safe to be called in both NMI and non-NMI context. This is a partial revert of the clean up patch c3bc8fd637a9 ("tracing: Centralize preemptirq tracepoints and unify their usage") that adds back the direct calls into the latency tracer. It also only calls the trace events when not in NMI. Link: http://lkml.kernel.org/r/20180809210654.622445925@goodmis.org Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Fixes: c3bc8fd637a9 ("tracing: Centralize preemptirq tracepoints and unify their usage") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing/irqsoff: Handle preempt_count for different configsSteven Rostedt (VMware)2018-08-101-29/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I was hitting the following warning: WARNING: CPU: 0 PID: 1 at kernel/trace/trace_irqsoff.c:631 tracer_hardirqs_off+0x15/0x2a Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-rc6-test+ #13 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014 EIP: tracer_hardirqs_off+0x15/0x2a Code: ff 85 c0 74 0e 8b 45 00 8b 50 04 8b 45 04 e8 35 ff ff ff 5d c3 55 64 a1 cc 37 51 c1 a9 ff ff ff 7f 89 e5 53 89 d3 89 ca 75 02 <0f> 0b e8 90 fc ff ff 85 c0 74 07 89 d8 e8 0c ff ff ff 5b 5d c3 55 EAX: 80000000 EBX: c04337f0 ECX: c04338e3 EDX: c04338e3 ESI: c04337f0 EDI: c04338e3 EBP: f2aa1d68 ESP: f2aa1d64 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210046 CR0: 80050033 CR2: 00000000 CR3: 01668000 CR4: 001406f0 Call Trace: trace_irq_disable_rcuidle+0x63/0x6c trace_hardirqs_off+0x26/0x30 default_send_IPI_mask_allbutself_logical+0x31/0x93 default_send_IPI_allbutself+0x37/0x48 native_send_call_func_ipi+0x4d/0x6a smp_call_function_many+0x165/0x19d ? add_nops+0x34/0x34 ? trace_hardirqs_on_caller+0x2d/0x2d ? add_nops+0x34/0x34 smp_call_function+0x1f/0x23 on_each_cpu+0x15/0x43 ? trace_hardirqs_on_caller+0x2d/0x2d ? trace_hardirqs_on_caller+0x2d/0x2d ? trace_irq_disable_rcuidle+0x1/0x6c text_poke_bp+0xa0/0xc2 ? trace_hardirqs_on_caller+0x2d/0x2d arch_jump_label_transform+0xa7/0xcb ? trace_irq_disable_rcuidle+0x5/0x6c __jump_label_update+0x3e/0x6d jump_label_update+0x7d/0x81 static_key_slow_inc_cpuslocked+0x58/0x6d static_key_slow_inc+0x19/0x20 tracepoint_probe_register_prio+0x19e/0x1d1 ? start_critical_timings+0x1c/0x1c tracepoint_probe_register+0xf/0x11 irqsoff_tracer_init+0x21/0xf2 tracer_init+0x16/0x1a trace_selftest_startup_irqsoff+0x25/0xc4 run_tracer_selftest+0xca/0x131 register_tracer+0xd5/0x172 ? trace_event_define_fields_preemptirq_template+0x45/0x45 init_irqsoff_tracer+0xd/0x11 do_one_initcall+0xab/0x1e8 ? rcu_read_lock_sched_held+0x3d/0x44 ? trace_initcall_level+0x52/0x86 kernel_init_freeable+0x195/0x21a ? rest_init+0xb4/0xb4 kernel_init+0xd/0xe4 ret_from_fork+0x2e/0x38 It is due to running a CONFIG_PREEMPT_VOLUNTARY kernel, which would trigger this warning every time: WARN_ON_ONCE(preempt_count()); Because on CONFIG_PREEMPT_VOLUNTARY, preempt_count() is always zero. This warning is to make sure preempt_count is set because tracer_hardirqs_on() does a preempt_enable_notrace() to make the preempt_trace() work properly, as being called by a trace event, the trace event code disables preemption, and the tracer wants to know what the preemption was before it was called. Instead of enabling preemption like this, just record the preempt_count, subtract PREEMPT_DISABLE_OFFSET from it (which is zero with !CONFIG_PREEMPT set), and pass that value to the necessary functions, which should use the passed in parameter instead of calling preempt_count() directly. Fixes: da5b3ebb45277 ("tracing: irqsoff: Account for additional preempt_disable") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and ↵Steven Rostedt (VMware)2018-08-102-28/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | unify their usage" Joel Fernandes created a nice patch that cleaned up the duplicate hooks used by lockdep and irqsoff latency tracer. It made both use tracepoints. But it caused lockdep to trigger several false positives. We have not figured out why yet, but removing lockdep from using the trace event hooks and just call its helper functions directly (like it use to), makes the problem go away. This is a partial revert of the clean up patch c3bc8fd637a9 ("tracing: Centralize preemptirq tracepoints and unify their usage") that adds direct calls for lockdep, but also keeps most of the clean up done to get rid of the horrible preprocessor if statements. Link: http://lkml.kernel.org/r/20180806155058.5ee875f4@gandalf.local.home Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Fixes: c3bc8fd637a9 ("tracing: Centralize preemptirq tracepoints and unify their usage") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: irqsoff: Account for additional preempt_disableJoel Fernandes (Google)2018-08-061-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recently we tried to make the preemptirqsoff tracer to use irqsoff tracepoint probes. However this causes issues as reported by Masami: [2.271078] Testing tracer preemptirqsoff: .. no entries found ..FAILED! [2.381015] WARNING: CPU: 0 PID: 1 at /home/mhiramat/ksrc/linux/kernel/ trace/trace.c:1512 run_tracer_selftest+0xf3/0x154 This is due to the tracepoint code increasing the preempt nesting count by calling an additional preempt_disable before calling into the preemptoff tracer which messes up the preempt_count() check in tracer_hardirqs_off. To fix this, make the irqsoff tracer probes balance the additional outer preempt_disable with a preempt_enable_notrace. The other way to fix this is to just use SRCU for all tracepoints. However we can't do that because we can't use NMIs from RCU context. Link: http://lkml.kernel.org/r/20180806034049.67949-1-joel@joelfernandes.org Fixes: c3bc8fd637a9 ("tracing: Centralize preemptirq tracepoints and unify their usage") Fixes: e6753f23d961 ("tracepoint: Make rcuidle tracepoint callers use SRCU") Reported-by: Masami Hiramatsu <mhiramat@kernel.org> Tested-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * trace: Use rcu_dereference_raw for hooks from trace-event subsystemJoel Fernandes (Google)2018-08-031-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since we switched to using SRCU for tracepoints used in the idle path, we can no longer use rcu_dereference_sched for dereferencing points in trace-event hooks. Since tracepoints can now use either SRCU or sched-RCU, just use rcu_dereference_raw for traceevents just like we're doing when dereferencing the tracepoint table. This prevents an RCU warning reported by Masami: [ 282.060593] WARNING: can't dereference registers at 00000000f3c7f62b [ 282.063200] ============================= [ 282.064082] WARNING: suspicious RCU usage [ 282.064963] 4.18.0-rc6+ #15 Tainted: G W [ 282.066048] ----------------------------- [ 282.066923] /home/mhiramat/ksrc/linux/kernel/trace/trace_events.c:242 suspicious rcu_dereference_check() usage! [ 282.068974] [ 282.068974] other info that might help us debug this: [ 282.068974] [ 282.070770] [ 282.070770] RCU used illegally from idle CPU! [ 282.070770] rcu_scheduler_active = 2, debug_locks = 1 [ 282.072938] RCU used illegally from extended quiescent state! [ 282.074183] no locks held by swapper/0/0. [ 282.075071] [ 282.075071] stack backtrace: [ 282.076121] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W [ 282.077782] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) [ 282.079604] Call Trace: [ 282.080212] <IRQ> [ 282.080755] dump_stack+0x85/0xcb [ 282.081523] trace_event_ignore_this_pid+0x66/0x70 [ 282.082541] trace_event_raw_event_preemptirq_template+0xa2/0xb0 [ 282.083774] ? interrupt_entry+0xc4/0xe0 [ 282.084665] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 282.085669] trace_hardirqs_off_caller+0x90/0xd0 [ 282.086597] trace_hardirqs_off_thunk+0x1a/0x1c [ 282.087433] ? call_function_interrupt+0xa/0x20 [ 282.088201] interrupt_entry+0xc4/0xe0 [ 282.088848] ? call_function_interrupt+0xa/0x20 [ 282.089579] </IRQ> [ 282.090029] ? native_safe_halt+0x2/0x10 [ 282.090695] ? default_idle+0x1f/0x160 [ 282.091330] ? default_idle_call+0x24/0x40 [ 282.091997] ? do_idle+0x210/0x250 [ 282.092658] ? cpu_startup_entry+0x6f/0x80 [ 282.093338] ? start_kernel+0x49d/0x4bd [ 282.093987] ? secondary_startup_64+0xa5/0xb0 Link: http://lkml.kernel.org/r/20180803023407.225852-1-joel@joelfernandes.org Reported-by: Masami Hiramatsu <mhiramat@kernel.org> Tested-by: Masami Hiramatsu <mhiramat@kernel.org> Fixes: e6753f23d961 ("tracepoint: Make rcuidle tracepoint callers use SRCU") Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing/kprobes: Fix within_notrace_func() to check only notrace functionsMasami Hiramatsu2018-08-021-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix within_notrace_func() to check only notrace functions and to ignore the kprobe-event which can not solve symbol addresses. within_notrace_func() returns true if the given kprobe events probe point seems to be out-of-range. But that is not the correct place to check for it, it should be done in kprobes afterwards. kprobe-events allow users to define a probe point on "currently unloaded module" so that it can trace the event during module load. In this case, the user will put a probe on a symbol which is not in kallsyms yet and it hits the within_notrace_func(). As a result, kprobe-events always refuses if user defines a probe on a "currenly unloaded module". Fixes: commit 45408c4f9250 ("tracing: kprobes: Prohibit probing on notrace function") Link: http://lkml.kernel.org/r/153319624799.29007.13604430345640129926.stgit@devbox Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * ftrace: Use true and false for boolean values in ops_references_rec()Gustavo A. R. Silva2018-08-011-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | Return statements in functions returning bool should use true or false instead of an integer value. This code was detected with the help of Coccinelle. Link: http://lkml.kernel.org/r/20180802010056.GA31012@embeddedor.com Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * ring-buffer: Make ring_buffer_record_is_set_on() return boolSteven Rostedt (VMware)2018-08-011-1/+1
| | | | | | | | | | | | | | The value of ring_buffer_record_is_set_on() is either true or false, so have its return value be bool. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * ring-buffer: Make ring_buffer_record_is_on() return boolSteven Rostedt (VMware)2018-08-011-1/+1
| | | | | | | | | | | | | | The value of ring_buffer_record_is_on() is either true or false, so have its return value be bool. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Make tracer_tracing_is_on() return boolSteven Rostedt (VMware)2018-08-012-2/+2
| | | | | | | | | | | | | | | | There's code that expects tracer_tracing_is_on() to be either true or false, not some random number. Currently, it should only return one or zero, but just in case, change its return value to bool, to enforce it. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread existsSteven Rostedt (VMware)2018-08-011-1/+1
| | | | | | | | | | | | | | The start function of the hwlat tracer should never be called when the hwlat thread already exists. If it is called, do a WARN_ON(). Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * ftrace: Add missing check for existing hwlat threadErica Bugden2018-08-011-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The hwlat tracer uses a kernel thread to measure latencies. The function that creates this kernel thread, start_kthread(), can be called when the tracer is initialized and when the tracer is explicitly enabled. start_kthread() does not check if there is an existing hwlat kernel thread and will create a new one each time it is called. This causes the reference to the previous thread to be lost. Without the thread reference, the old kernel thread becomes unstoppable and continues to use CPU time even after the hwlat tracer has been disabled. This problem can be observed when a system is booted with tracing enabled and the hwlat tracer is configured like this: echo hwlat > current_tracer; echo 1 > tracing_on Add the missing check for an existing kernel thread in start_kthread() to prevent this problem. This function and the rest of the hwlat kernel thread setup and teardown are already serialized because they are called through the tracer core code with trace_type_lock held. [ Note, this only fixes the symptom. The real fix was not to call this function when tracing_on was already one. But this still makes the code more robust, so we'll add it. ] Link: http://lkml.kernel.org/r/1533120354-22923-1-git-send-email-erica.bugden@linutronix.de Signed-off-by: Erica Bugden <erica.bugden@linutronix.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Do not call start/stop() functions when tracing_on does not changeSteven Rostedt (VMware)2018-08-011-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, when one echo's in 1 into tracing_on, the current tracer's "start()" function is executed, even if tracing_on was already one. This can lead to strange side effects. One being that if the hwlat tracer is enabled, and someone does "echo 1 > tracing_on" into tracing_on, the hwlat tracer's start() function is called again which will recreate another kernel thread, and make it unable to remove the old one. Link: http://lkml.kernel.org/r/1533120354-22923-1-git-send-email-erica.bugden@linutronix.de Cc: stable@vger.kernel.org Fixes: 2df8f8a6a897e ("tracing: Fix regression with irqsoff tracer and tracing_on file") Reported-by: Erica Bugden <erica.bugden@linutronix.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Centralize preemptirq tracepoints and unify their usageJoel Fernandes (Google)2018-07-316-202/+162
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch detaches the preemptirq tracepoints from the tracers and keeps it separate. Advantages: * Lockdep and irqsoff event can now run in parallel since they no longer have their own calls. * This unifies the usecase of adding hooks to an irqsoff and irqson event, and a preemptoff and preempton event. 3 users of the events exist: - Lockdep - irqsoff and preemptoff tracers - irqs and preempt trace events The unification cleans up several ifdefs and makes the code in preempt tracer and irqsoff tracers simpler. It gets rid of all the horrific ifdeferry around PROVE_LOCKING and makes configuration of the different users of the tracepoints more easy and understandable. It also gets rid of the time_* function calls from the lockdep hooks used to call into the preemptirq tracer which is not needed anymore. The negative delta in lines of code in this patch is quite large too. In the patch we introduce a new CONFIG option PREEMPTIRQ_TRACEPOINTS as a single point for registering probes onto the tracepoints. With this, the web of config options for preempt/irq toggle tracepoints and its users becomes: PREEMPT_TRACER PREEMPTIRQ_EVENTS IRQSOFF_TRACER PROVE_LOCKING | | \ | | \ (selects) / \ \ (selects) / TRACE_PREEMPT_TOGGLE ----> TRACE_IRQFLAGS \ / \ (depends on) / PREEMPTIRQ_TRACEPOINTS Other than the performance tests mentioned in the previous patch, I also ran the locking API test suite. I verified that all tests cases are passing. I also injected issues by not registering lockdep probes onto the tracepoints and I see failures to confirm that the probes are indeed working. This series + lockdep probes not registered (just to inject errors): [ 0.000000] hard-irqs-on + irq-safe-A/21: ok | ok | ok | [ 0.000000] soft-irqs-on + irq-safe-A/21: ok | ok | ok | [ 0.000000] sirq-safe-A => hirqs-on/12:FAILED|FAILED| ok | [ 0.000000] sirq-safe-A => hirqs-on/21:FAILED|FAILED| ok | [ 0.000000] hard-safe-A + irqs-on/12:FAILED|FAILED| ok | [ 0.000000] soft-safe-A + irqs-on/12:FAILED|FAILED| ok | [ 0.000000] hard-safe-A + irqs-on/21:FAILED|FAILED| ok | [ 0.000000] soft-safe-A + irqs-on/21:FAILED|FAILED| ok | [ 0.000000] hard-safe-A + unsafe-B #1/123: ok | ok | ok | [ 0.000000] soft-safe-A + unsafe-B #1/123: ok | ok | ok | With this series + lockdep probes registered, all locking tests pass: [ 0.000000] hard-irqs-on + irq-safe-A/21: ok | ok | ok | [ 0.000000] soft-irqs-on + irq-safe-A/21: ok | ok | ok | [ 0.000000] sirq-safe-A => hirqs-on/12: ok | ok | ok | [ 0.000000] sirq-safe-A => hirqs-on/21: ok | ok | ok | [ 0.000000] hard-safe-A + irqs-on/12: ok | ok | ok | [ 0.000000] soft-safe-A + irqs-on/12: ok | ok | ok | [ 0.000000] hard-safe-A + irqs-on/21: ok | ok | ok | [ 0.000000] soft-safe-A + irqs-on/21: ok | ok | ok | [ 0.000000] hard-safe-A + unsafe-B #1/123: ok | ok | ok | [ 0.000000] soft-safe-A + unsafe-B #1/123: ok | ok | ok | Link: http://lkml.kernel.org/r/20180730222423.196630-4-joel@joelfernandes.org Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracepoint: Make rcuidle tracepoint callers use SRCUJoel Fernandes (Google)2018-07-301-1/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In recent tests with IRQ on/off tracepoints, a large performance overhead ~10% is noticed when running hackbench. This is root caused to calls to rcu_irq_enter_irqson and rcu_irq_exit_irqson from the tracepoint code. Following a long discussion on the list [1] about this, we concluded that srcu is a better alternative for use during rcu idle. Although it does involve extra barriers, its lighter than the sched-rcu version which has to do additional RCU calls to notify RCU idle about entry into RCU sections. In this patch, we change the underlying implementation of the trace_*_rcuidle API to use SRCU. This has shown to improve performance alot for the high frequency irq enable/disable tracepoints. Test: Tested idle and preempt/irq tracepoints. Here are some performance numbers: With a run of the following 30 times on a single core x86 Qemu instance with 1GB memory: hackbench -g 4 -f 2 -l 3000 Completion times in seconds. CONFIG_PROVE_LOCKING=y. No patches (without this series) Mean: 3.048 Median: 3.025 Std Dev: 0.064 With Lockdep using irq tracepoints with RCU implementation: Mean: 3.451 (-11.66 %) Median: 3.447 (-12.22%) Std Dev: 0.049 With Lockdep using irq tracepoints with SRCU implementation (this series): Mean: 3.020 (I would consider the improvement against the "without this series" case as just noise). Median: 3.013 Std Dev: 0.033 [1] https://patchwork.kernel.org/patch/10344297/ [remove rcu_read_lock_sched_notrace as its the equivalent of preempt_disable_notrace and is unnecessary to call in tracepoint code] Link: http://lkml.kernel.org/r/20180730222423.196630-3-joel@joelfernandes.org Cleaned-up-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> [ Simplified WARN_ON_ONCE() ] Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * lockdep: Use this_cpu_ptr instead of get_cpu_var statsJoel Fernandes (Google)2018-07-301-9/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | get_cpu_var disables preemption which has the potential to call into the preemption disable trace points causing some complications. There's also no need to disable preemption in uses of get_lock_stats anyway since preempt is already disabled. So lets simplify the code. Link: http://lkml.kernel.org/r/20180730222423.196630-2-joel@joelfernandes.org Suggested-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * selftest/ftrace: Move kprobe selftest function to separate compile unitFrancis Deslauriers2018-07-304-11/+23
| | | | | | | | | | | | | | | | | | | | | | | | Move selftest function to its own compile unit so it can be compiled with the ftrace cflags (CC_FLAGS_FTRACE) allowing it to be probed during the ftrace startup tests. Link: http://lkml.kernel.org/r/153294604271.32740.16490677128630177030.stgit@devbox Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: kprobes: Prohibit probing on notrace functionMasami Hiramatsu2018-07-302-9/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Prohibit kprobe-events probing on notrace functions. Since probing on a notrace function can cause a recursive event call. In most cases those are just skipped, but in some cases it falls into an infinite recursive call. This protection can be disabled by the kconfig CONFIG_KPROBE_EVENTS_ON_NOTRACE=y, but it is highly recommended to keep it "n" for normal kernel builds. Note that this is only available if "kprobes on ftrace" has been implemented on the target arch and CONFIG_KPROBES_ON_FTRACE=y. Link: http://lkml.kernel.org/r/153294601436.32740.10557881188933661239.stgit@devbox Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Tested-by: Francis Deslauriers <francis.deslauriers@efficios.com> [ Slight grammar and spelling fixes ] Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: preemptirq_delay_run() can be statickbuild test robot2018-07-271-1/+1
| | | | | | | | | | | | | | | | Automatically found by kbuild test robot. Fixes: ffdc73a3b2ad ("lib: Add module for testing preemptoff/irqsoff latency tracers") Signed-off-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing/kprobes: Simplify the logic of enable_trace_kprobe()Steven Rostedt (VMware)2018-07-271-18/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The function enable_trace_kprobe() performs slightly differently if the file parameter is passed in as NULL on non-NULL. Instead of checking file twice, move the code between the two tests into a static inline helper function to make the code easier to follow. Link: http://lkml.kernel.org/r/20180725224728.7b1d5db2@vmware.local.home Link: http://lkml.kernel.org/r/20180726121152.4dd54330@gandalf.local.home Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Remove orphaned function ftrace_nr_registered_ops()Masami Hiramatsu2018-07-261-24/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove ftrace_nr_registered_ops() because it is no longer used. ftrace_nr_registered_ops() has been introduced by commit ea701f11da44 ("ftrace: Add selftest to test function trace recursion protection"), but its caller has been removed by commit 05cbbf643b8e ("tracing: Fix selftest function recursion accounting"). So it is not called anymore. Link: http://lkml.kernel.org/r/153260907227.12474.5234899025934963683.stgit@devbox Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Remove orphaned function using_ftrace_ops_list_func().Masami Hiramatsu2018-07-262-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove using_ftrace_ops_list_func() since it is no longer used. Using ftrace_ops_list_func() has been introduced by commit 7eea4fce0246 ("tracing/stack_trace: Skip 4 instead of 3 when using ftrace_ops_list_func") as a helper function, but its caller has been removed by commit 72ac426a5bb0 ("tracing: Clean up stack tracing and fix fentry updates"). So it is not called anymore. Link: http://lkml.kernel.org/r/153260904427.12474.9952096317439329851.stgit@devbox Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing: Make unregister_trigger() staticSteven Rostedt (VMware)2018-07-262-6/+3
| | | | | | | | | | | | | | | | Nothing uses unregister_trigger() outside of trace_events_trigger.c file, thus it should be static. Not sure why this was ever converted, because its counter part, register_trigger(), was always static. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * lib: Add module for testing preemptoff/irqsoff latency tracersJoel Fernandes (Google)2018-07-263-0/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here we introduce a test module for introducing a long preempt or irq disable delay in the kernel which the preemptoff or irqsoff tracers can detect. This module is to be used only for test purposes and is default disabled. Following is the expected output (only briefly shown) that can be parsed to verify that the tracers are working correctly. We will use this from the kselftests in future patches. For the preemptoff tracer: echo preemptoff > /d/tracing/current_tracer sleep 1 insmod ./preemptirq_delay_test.ko test_mode=preempt delay=500000 sleep 1 bash-4.3# cat /d/tracing/trace preempt -1066 2...2 0us@: preemptirq_delay_run <-preemptirq_delay_run preempt -1066 2...2 500002us : preemptirq_delay_run <-preemptirq_delay_run preempt -1066 2...2 500004us : tracer_preempt_on <-preemptirq_delay_run preempt -1066 2...2 500012us : <stack trace> => kthread => ret_from_fork For the irqsoff tracer: echo irqsoff > /d/tracing/current_tracer sleep 1 insmod ./preemptirq_delay_test.ko test_mode=irq delay=500000 sleep 1 bash-4.3# cat /d/tracing/trace irq dis -1069 1d..1 0us@: preemptirq_delay_run irq dis -1069 1d..1 500001us : preemptirq_delay_run irq dis -1069 1d..1 500002us : tracer_hardirqs_on <-preemptirq_delay_run irq dis -1069 1d..1 500005us : <stack trace> => ret_from_fork Link: http://lkml.kernel.org/r/20180712213611.GA8743@joelaf.mtv.corp.google.com Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Julia Cartwright <julia@ni.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Glexiner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> [ Erick is a co-developer of this commit ] Signed-off-by: Erick Reyes <erickreyes@google.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing/irqsoff: Split reset into separate functionsJoel Fernandes (Google)2018-07-261-3/+19
| | | | | | | | | | | | | | | | | | | | | | Split reset functions into seperate functions in preparation of future patches that need to do tracer specific reset. Link: http://lkml.kernel.org/r/20180628182149.226164-4-joel@joelfernandes.org Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* | Merge branch 'for-linus' of ↵Linus Torvalds2018-08-202-7/+6
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching Pull livepatching updates from Jiri Kosina: "Code cleanups from Kamalesh Babulal" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching: livepatch: Validate module/old func name length livepatch: Remove reliable stacktrace check in klp_try_switch_task()
| * \ Merge branch 'for-4.19/upstream' into for-linusJiri Kosina2018-08-201-7/+0
| |\ \
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