linux/kernel/events/core.c, branch v5.0

perf/x86: Add check_period PMU callback

2019-02-11T10:46:43Z

Vince (and later on Ravi) reported crashes in the BTS code during fuzzing with the following backtrace: general protection fault: 0000 [#1] SMP PTI ... RIP: 0010:perf_prepare_sample+0x8f/0x510 ... Call Trace: ? intel_pmu_drain_bts_buffer+0x194/0x230 intel_pmu_drain_bts_buffer+0x160/0x230 ? tick_nohz_irq_exit+0x31/0x40 ? smp_call_function_single_interrupt+0x48/0xe0 ? call_function_single_interrupt+0xf/0x20 ? call_function_single_interrupt+0xa/0x20 ? x86_schedule_events+0x1a0/0x2f0 ? x86_pmu_commit_txn+0xb4/0x100 ? find_busiest_group+0x47/0x5d0 ? perf_event_set_state.part.42+0x12/0x50 ? perf_mux_hrtimer_restart+0x40/0xb0 intel_pmu_disable_event+0xae/0x100 ? intel_pmu_disable_event+0xae/0x100 x86_pmu_stop+0x7a/0xb0 x86_pmu_del+0x57/0x120 event_sched_out.isra.101+0x83/0x180 group_sched_out.part.103+0x57/0xe0 ctx_sched_out+0x188/0x240 ctx_resched+0xa8/0xd0 __perf_event_enable+0x193/0x1e0 event_function+0x8e/0xc0 remote_function+0x41/0x50 flush_smp_call_function_queue+0x68/0x100 generic_smp_call_function_single_interrupt+0x13/0x30 smp_call_function_single_interrupt+0x3e/0xe0 call_function_single_interrupt+0xf/0x20 The reason is that while event init code does several checks for BTS events and prevents several unwanted config bits for BTS event (like precise_ip), the PERF_EVENT_IOC_PERIOD allows to create BTS event without those checks being done. Following sequence will cause the crash: If we create an 'almost' BTS event with precise_ip and callchains, and it into a BTS event it will crash the perf_prepare_sample() function because precise_ip events are expected to come in with callchain data initialized, but that's not the case for intel_pmu_drain_bts_buffer() caller. Adding a check_period callback to be called before the period is changed via PERF_EVENT_IOC_PERIOD. It will deny the change if the event would become BTS. Plus adding also the limit_period check as well. Reported-by: Vince Weaver Signed-off-by: Jiri Olsa Acked-by: Peter Zijlstra Cc: Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Naveen N. Rao Cc: Ravi Bangoria Cc: Stephane Eranian Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20190204123532.GA4794@krava Signed-off-by: Ingo Molnar

perf core: Fix perf_proc_update_handler() bug

2019-01-18T14:10:38Z

The perf_proc_update_handler() handles /proc/sys/kernel/perf_event_max_sample_rate syctl variable. When the PMU IRQ handler timing monitoring is disabled, i.e, when /proc/sys/kernel/perf_cpu_time_max_percent is equal to 0 or 100, then no modification to sysctl_perf_event_sample_rate is allowed to prevent possible hang from wrong values. The problem is that the test to prevent modification is made after the sysctl variable is modified in perf_proc_update_handler(). You get an error: $ echo 10001 >/proc/sys/kernel/perf_event_max_sample_rate echo: write error: invalid argument But the value is still modified causing all sorts of inconsistencies: $ cat /proc/sys/kernel/perf_event_max_sample_rate 10001 This patch fixes the problem by moving the parsing of the value after the test. Committer testing: # echo 100 > /proc/sys/kernel/perf_cpu_time_max_percent # echo 10001 > /proc/sys/kernel/perf_event_max_sample_rate -bash: echo: write error: Invalid argument # cat /proc/sys/kernel/perf_event_max_sample_rate 10001 # Signed-off-by: Stephane Eranian Reviewed-by: Andi Kleen Reviewed-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Kan Liang Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1547169436-6266-1-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57Z

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds

Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-12-26T22:45:18Z

Pull perf updates from Ingo Molnar: "The main changes in this cycle on the kernel side: - rework kprobes blacklist handling (Masami Hiramatsu) - misc cleanups on the tooling side these areas were the main focus: - 'perf trace' enhancements (Arnaldo Carvalho de Melo) - 'perf bench' enhancements (Davidlohr Bueso) - 'perf record' enhancements (Alexey Budankov) - 'perf annotate' enhancements (Jin Yao) - 'perf top' enhancements (Jiri Olsa) - Intel hw tracing enhancements (Adrian Hunter) - ARM hw tracing enhancements (Leo Yan, Mathieu Poirier) - ... plus lots of other enhancements, cleanups and fixes" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (171 commits) tools uapi asm: Update asm-generic/unistd.h copy perf symbols: Relax checks on perf-PID.map ownership perf trace: Wire up the fadvise 'advice' table generator perf beauty: Add generator for fadvise64's 'advice' arg constants tools headers uapi: Grab a copy of fadvise.h perf beauty mmap: Print mmap's 'offset' arg in hexadecimal perf beauty mmap: Print PROT_READ before PROT_EXEC to match strace output perf trace beauty: Beautify arch_prctl()'s arguments perf trace: When showing string prefixes show prefix + ??? for unknown entries perf trace: Move strarrays to beauty.h for further reuse perf beauty: Wire up the x86_arch prctl code table generator perf beauty: Add a string table generator for x86's 'arch_prctl' codes tools include arch: Grab a copy of x86's prctl.h perf trace: Show NULL when syscall pointer args are 0 perf trace: Enclose the errno strings with () perf augmented_raw_syscalls: Copy 'access' arg as well perf trace: Add alignment spaces after the closing parens perf trace beauty: Print O_RDONLY when (flags & O_ACCMODE) == 0 perf trace: Allow asking for not suppressing common string prefixes perf trace: Add a prefix member to the strarray class ...

perf: Fix typos in comments

2018-12-03T10:22:32Z

Fix two typos in kernel/events/*. No change in functionality intended. Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Linus Torvalds Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

events: Replace synchronize_sched() with synchronize_rcu()

2018-11-27T17:21:44Z

Now that synchronize_rcu() waits for preempt-disable regions of code as well as RCU read-side critical sections, synchronize_sched() can be replaced by synchronize_rcu(). This commit therefore makes this change. Signed-off-by: Paul E. McKenney Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Namhyung Kim

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-11-04T01:13:43Z

Pull perf updates and fixes from Ingo Molnar: "These are almost all tooling updates: 'perf top', 'perf trace' and 'perf script' fixes and updates, an UAPI header sync with the merge window versions, license marker updates, much improved Sparc support from David Miller, and a number of fixes" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (66 commits) perf intel-pt/bts: Calculate cpumode for synthesized samples perf intel-pt: Insert callchain context into synthesized callchains perf tools: Don't clone maps from parent when synthesizing forks perf top: Start display thread earlier tools headers uapi: Update linux/if_link.h header copy tools headers uapi: Update linux/netlink.h header copy tools headers: Sync the various kvm.h header copies tools include uapi: Update linux/mmap.h copy perf trace beauty: Use the mmap flags table generated from headers perf beauty: Wire up the mmap flags table generator to the Makefile perf beauty: Add a generator for MAP_ mmap's flag constants tools include uapi: Update asound.h copy tools arch uapi: Update asm-generic/unistd.h and arm64 unistd.h copies tools include uapi: Update linux/fs.h copy perf callchain: Honour the ordering of PERF_CONTEXT_{USER,KERNEL,etc} perf cs-etm: Correct CPU mode for samples perf unwind: Take pgoff into account when reporting elf to libdwfl perf top: Do not use overwrite mode by default perf top: Allow disabling the overwrite mode perf trace: Beautify mount's first pathname arg ...

Merge tag 'trace-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2018-10-30T16:49:56Z

Pull tracing updates from Steven Rostedt: "The biggest change here is the updates to kprobes Back in January I posted patches to create function based events. These were the events that you suggested I make to allow developers to easily create events in code where no trace event exists. After posting those changes for review, it was suggested that we implement this instead with kprobes. The problem with kprobes is that the interface is too complex and needs to be simplified. Masami Hiramatsu posted patches in March and I've been playing with them a bit. There's been a bit of clean up in the kprobe code that was inspired by the function based event patches, and a couple of enhancements to the kprobe event interface. - If the arch supports it (we added support for x86), you can place a kprobe event at the start of a function and use $arg1, $arg2, etc to reference the arguments of a function. (Before you needed to know what register or where on the stack the argument was). - The second is a way to see array of events. For example, if you reference a mac address, you can add: echo 'p:mac ip_rcv perm_addr=+574($arg2):x8[6]' > kprobe_events And this will produce: mac: (ip_rcv+0x0/0x140) perm_addr={0x52,0x54,0x0,0xc0,0x76,0xec} Other changes include - Exporting trace_dump_stack to modules - Have the stack tracer trace the entire stack (stop trying to remove tracing itself, as we keep removing too much). - Added support for SDT in uprobes" [ SDT - "Statically Defined Tracing" are userspace markers for tracing. Let's not use random TLA's in explanations unless they are fairly well-established as generic (at least for kernel people) - Linus ] * tag 'trace-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (24 commits) tracing: Have stack tracer trace full stack tracing: Export trace_dump_stack to modules tracing: probeevent: Fix uninitialized used of offset in parse args tracing/kprobes: Allow kprobe-events to record module symbol tracing/kprobes: Check the probe on unloaded module correctly tracing/uprobes: Fix to return -EFAULT if copy_from_user failed tracing: probeevent: Add $argN for accessing function args x86: ptrace: Add function argument access API tracing: probeevent: Add array type support tracing: probeevent: Add symbol type tracing: probeevent: Unify fetch_insn processing common part tracing: probeevent: Append traceprobe_ for exported function tracing: probeevent: Return consumed bytes of dynamic area tracing: probeevent: Unify fetch type tables tracing: probeevent: Introduce new argument fetching code tracing: probeevent: Remove NOKPROBE_SYMBOL from print functions tracing: probeevent: Cleanup argument field definition tracing: probeevent: Cleanup print argument functions trace_uprobe: support reference counter in fd-based uprobe perf probe: Support SDT markers having reference counter (semaphore) ...

perf/core: Clean up inconsisent indentation

2018-10-30T08:51:58Z

Replace a bunch of spaces with tab, cleans up indentation Signed-off-by: Colin Ian King Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: kernel-janitors@vger.kernel.org Link: http://lkml.kernel.org/r/20181029233211.21475-1-colin.king@canonical.com Signed-off-by: Ingo Molnar

trace_uprobe: support reference counter in fd-based uprobe

2018-10-11T02:14:17Z

This patch enables uprobes with reference counter in fd-based uprobe. Highest 32 bits of perf_event_attr.config is used to stored offset of the reference count (semaphore). Format information in /sys/bus/event_source/devices/uprobe/format/ is updated to reflect this new feature. Link: http://lkml.kernel.org/r/20181002053636.1896903-1-songliubraving@fb.com Cc: Oleg Nesterov Acked-by: Peter Zijlstra (Intel) Reviewed-and-tested-by: Ravi Bangoria Signed-off-by: Song Liu Signed-off-by: Steven Rostedt (VMware)