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2018-05-05perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[]Peter Zijlstra1-2/+5
> kernel/events/ring_buffer.c:871 perf_mmap_to_page() warn: potential spectre issue 'rb->aux_pages' Userspace controls @pgoff through the fault address. Sanitize the array index before doing the array dereference. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-05-03Merge tag 'trace-v4.17-rc1-2' of ↵Linus Torvalds1-4/+3
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "Various fixes in tracing: - Tracepoints should not give warning on OOM failures - Use special field for function pointer in trace event - Fix igrab issues in uprobes - Fixes to the new histogram triggers" * tag 'trace-v4.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracepoint: Do not warn on ENOMEM tracing: Add field modifier parsing hist error for hist triggers tracing: Add field parsing hist error for hist triggers tracing: Restore proper field flag printing when displaying triggers tracing: initcall: Ordered comparison of function pointers tracing: Remove igrab() iput() call from uprobes.c tracing: Fix bad use of igrab in trace_uprobe.c
2018-04-26tracing: Remove igrab() iput() call from uprobes.cSong Liu1-4/+3
Caller of uprobe_register is required to keep the inode and containing mount point referenced. There was misuse of igrab() in uprobes.c and trace_uprobe.c. This is because igrab() will not prevent umount of the containing mount point. To fix this, we added path to struct trace_uprobe, which keeps the inode and containing mount reference. For uprobes.c, it is not necessary to call igrab() in uprobe_register(), as the caller is required to keep the inode reference. The igrab() is removed and comments on this requirement is added to uprobe_register(). Link: http://lkml.kernel.org/r/CAELBmZB2XX=qEOLAdvGG4cPx4GEntcSnWQquJLUK1ongRj35cA@mail.gmail.com Link: http://lkml.kernel.org/r/20180423172135.4050588-2-songliubraving@fb.com Cc: Ingo Molnar <mingo@redhat.com> Cc: Howard McLauchlan <hmclauchlan@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-04-17perf: Remove superfluous allocation error checkJiri Olsa1-8/+2
If the get_callchain_buffers fails to allocate the buffer it will decrease the nr_callchain_events right away. There's no point of checking the allocation error for nr_callchain_events > 1. Removing that check. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: syzkaller-bugs@googlegroups.com Cc: x86@kernel.org Link: http://lkml.kernel.org/r/20180415092352.12403-3-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-04-17perf: Fix sample_max_stack maximum checkJiri Olsa1-9/+12
The syzbot hit KASAN bug in perf_callchain_store having the entry stored behind the allocated bounds [1]. We miss the sample_max_stack check for the initial event that allocates callchain buffers. This missing check allows to create an event with sample_max_stack value bigger than the global sysctl maximum: # sysctl -a | grep perf_event_max_stack kernel.perf_event_max_stack = 127 # perf record -vv -C 1 -e cycles/max-stack=256/ kill ... perf_event_attr: size 112 ... sample_max_stack 256 ------------------------------------------------------------ sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 4 Note the '-C 1', which forces perf record to create just single event. Otherwise it opens event for every cpu, then the sample_max_stack check fails on the second event and all's fine. The fix is to run the sample_max_stack check also for the first event with callchains. [1] https://marc.info/?l=linux-kernel&m=152352732920874&w=2 Reported-by: syzbot+7c449856228b63ac951e@syzkaller.appspotmail.com Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: syzkaller-bugs@googlegroups.com Cc: x86@kernel.org Fixes: 97c79a38cd45 ("perf core: Per event callchain limit") Link: http://lkml.kernel.org/r/20180415092352.12403-2-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-04-17perf: Return proper values for user stack errorsJiri Olsa1-2/+2
Return immediately when we find issue in the user stack checks. The error value could get overwritten by following check for PERF_SAMPLE_REGS_INTR. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: syzkaller-bugs@googlegroups.com Cc: x86@kernel.org Fixes: 60e2364e60e8 ("perf: Add ability to sample machine state on interrupt") Link: http://lkml.kernel.org/r/20180415092352.12403-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-04-17perf/core: Store context switch out type in PERF_RECORD_SWITCH[_CPU_WIDE]Alexey Budankov1-0/+4
Store preempting context switch out event into Perf trace as a part of PERF_RECORD_SWITCH[_CPU_WIDE] record. Percentage of preempting and non-preempting context switches help understanding the nature of workloads (CPU or IO bound) that are running on a machine; The event is treated as preemption one when task->state value of the thread being switched out is TASK_RUNNING. Event type encoding is implemented using PERF_RECORD_MISC_SWITCH_OUT_PREEMPT bit; Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/9ff84e83-a0ca-dd82-a6d0-cb951689be74@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-04-12perf/core: Need CAP_SYS_ADMIN to create k/uprobe with perf_event_open()Song Liu1-0/+8
Non-root user cannot create kprobe or uprobe through the text-based interface (kprobe_events, uprobe_events),so they should not be able to create probes via perf_event_open() either. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Song Liu <songliubraving@fb.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 33ea4b24277b ("perf/core: Implement the 'perf_uprobe' PMU") Fixes: e12f03d7031a ("perf/core: Implement the 'perf_kprobe' PMU") Link: http://lkml.kernel.org/r/C0B2EFB5-C403-4BDB-9046-C14B3EE66999@fb.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-09perf/core: Fix use-after-free in uprobe_perf_close()Prashant Bhole1-0/+6
A use-after-free bug was caught by KASAN while running usdt related code (BCC project. bcc/tests/python/test_usdt2.py): ================================================================== BUG: KASAN: use-after-free in uprobe_perf_close+0x222/0x3b0 Read of size 4 at addr ffff880384f9b4a4 by task test_usdt2.py/870 CPU: 4 PID: 870 Comm: test_usdt2.py Tainted: G W 4.16.0-next-20180409 #215 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0xc7/0x15b ? show_regs_print_info+0x5/0x5 ? printk+0x9c/0xc3 ? kmsg_dump_rewind_nolock+0x6e/0x6e ? uprobe_perf_close+0x222/0x3b0 print_address_description+0x83/0x3a0 ? uprobe_perf_close+0x222/0x3b0 kasan_report+0x1dd/0x460 ? uprobe_perf_close+0x222/0x3b0 uprobe_perf_close+0x222/0x3b0 ? probes_open+0x180/0x180 ? free_filters_list+0x290/0x290 trace_uprobe_register+0x1bb/0x500 ? perf_event_attach_bpf_prog+0x310/0x310 ? probe_event_disable+0x4e0/0x4e0 perf_uprobe_destroy+0x63/0xd0 _free_event+0x2bc/0xbd0 ? lockdep_rcu_suspicious+0x100/0x100 ? ring_buffer_attach+0x550/0x550 ? kvm_sched_clock_read+0x1a/0x30 ? perf_event_release_kernel+0x3e4/0xc00 ? __mutex_unlock_slowpath+0x12e/0x540 ? wait_for_completion+0x430/0x430 ? lock_downgrade+0x3c0/0x3c0 ? lock_release+0x980/0x980 ? do_raw_spin_trylock+0x118/0x150 ? do_raw_spin_unlock+0x121/0x210 ? do_raw_spin_trylock+0x150/0x150 perf_event_release_kernel+0x5d4/0xc00 ? put_event+0x30/0x30 ? fsnotify+0xd2d/0xea0 ? sched_clock_cpu+0x18/0x1a0 ? __fsnotify_update_child_dentry_flags.part.0+0x1b0/0x1b0 ? pvclock_clocksource_read+0x152/0x2b0 ? pvclock_read_flags+0x80/0x80 ? kvm_sched_clock_read+0x1a/0x30 ? sched_clock_cpu+0x18/0x1a0 ? pvclock_clocksource_read+0x152/0x2b0 ? locks_remove_file+0xec/0x470 ? pvclock_read_flags+0x80/0x80 ? fcntl_setlk+0x880/0x880 ? ima_file_free+0x8d/0x390 ? lockdep_rcu_suspicious+0x100/0x100 ? ima_file_check+0x110/0x110 ? fsnotify+0xea0/0xea0 ? kvm_sched_clock_read+0x1a/0x30 ? rcu_note_context_switch+0x600/0x600 perf_release+0x21/0x40 __fput+0x264/0x620 ? fput+0xf0/0xf0 ? do_raw_spin_unlock+0x121/0x210 ? do_raw_spin_trylock+0x150/0x150 ? SyS_fchdir+0x100/0x100 ? fsnotify+0xea0/0xea0 task_work_run+0x14b/0x1e0 ? task_work_cancel+0x1c0/0x1c0 ? copy_fd_bitmaps+0x150/0x150 ? vfs_read+0xe5/0x260 exit_to_usermode_loop+0x17b/0x1b0 ? trace_event_raw_event_sys_exit+0x1a0/0x1a0 do_syscall_64+0x3f6/0x490 ? syscall_return_slowpath+0x2c0/0x2c0 ? lockdep_sys_exit+0x1f/0xaa ? syscall_return_slowpath+0x1a3/0x2c0 ? lockdep_sys_exit+0x1f/0xaa ? prepare_exit_to_usermode+0x11c/0x1e0 ? enter_from_user_mode+0x30/0x30 random: crng init done ? __put_user_4+0x1c/0x30 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x7f41d95f9340 RSP: 002b:00007fffe71e4268 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 000000000000000d RCX: 00007f41d95f9340 RDX: 0000000000000000 RSI: 0000000000002401 RDI: 000000000000000d RBP: 0000000000000000 R08: 00007f41ca8ff700 R09: 00007f41d996dd1f R10: 00007fffe71e41e0 R11: 0000000000000246 R12: 00007fffe71e4330 R13: 0000000000000000 R14: fffffffffffffffc R15: 00007fffe71e4290 Allocated by task 870: kasan_kmalloc+0xa0/0xd0 kmem_cache_alloc_node+0x11a/0x430 copy_process.part.19+0x11a0/0x41c0 _do_fork+0x1be/0xa20 do_syscall_64+0x198/0x490 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Freed by task 0: __kasan_slab_free+0x12e/0x180 kmem_cache_free+0x102/0x4d0 free_task+0xfe/0x160 __put_task_struct+0x189/0x290 delayed_put_task_struct+0x119/0x250 rcu_process_callbacks+0xa6c/0x1b60 __do_softirq+0x238/0x7ae The buggy address belongs to the object at ffff880384f9b480 which belongs to the cache task_struct of size 12928 It occurs because task_struct is freed before perf_event which refers to the task and task flags are checked while teardown of the event. perf_event_alloc() assigns task_struct to hw.target of perf_event, but there is no reference counting for it. As a fix we get_task_struct() in perf_event_alloc() at above mentioned assignment and put_task_struct() in _free_event(). Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 63b6da39bb38e8f1a1ef3180d32a39d6 ("perf: Fix perf_event_exit_task() race") Link: http://lkml.kernel.org/r/20180409100346.6416-1-bhole_prashant_q7@lab.ntt.co.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-29perf/x86/pt, coresight: Clean up address filter structureAlexander Shishkin1-8/+18
This is a cosmetic patch that deals with the address filter structure's ambiguous fields 'filter' and 'range'. The former stands to mean that the filter's *action* should be to filter the traces to its address range if it's set or stop tracing if it's unset. This is confusing and hard on the eyes, so this patch replaces it with 'action' enum. The 'range' field is completely redundant (meaning that the filter is an address range as opposed to a single address trigger), as we can use zero size to mean the same thing. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20180329120648.11902-1-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-29Merge branch 'perf/urgent' into perf/coreIngo Molnar1-13/+6
Conflicts: kernel/events/hw_breakpoint.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-28perf/hwbp: Simplify the perf-hwbp code, fix documentationLinus Torvalds1-23/+7
Annoyingly, modify_user_hw_breakpoint() unnecessarily complicates the modification of a breakpoint - simplify it and remove the pointless local variables. Also update the stale Docbook while at it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-24Merge branch 'perf/urgent' into perf/core, to pick up fixesIngo Molnar1-5/+16
With the cherry-picked perf/urgent commit merged separately we can now merge all the fixes without conflicts. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-20perf/cgroup: Fix child event counting bugSong Liu1-5/+16
When a perf_event is attached to parent cgroup, it should count events for all children cgroups: parent_group <---- perf_event \ - child_group <---- process(es) However, in our tests, we found this perf_event cannot report reliable results. Here is an example case: # create cgroups mkdir -p /sys/fs/cgroup/p/c # start perf for parent group perf stat -e instructions -G "p" # on another console, run test process in child cgroup: stressapptest -s 2 -M 1000 & echo $! > /sys/fs/cgroup/p/c/cgroup.procs # after the test process is done, stop perf in the first console shows <not counted> instructions p The instruction should not be "not counted" as the process runs in the child cgroup. We found this is because perf_event->cgrp and cpuctx->cgrp are not identical, thus perf_event->cgrp are not updated properly. This patch fixes this by updating perf_cgroup properly for ancestor cgroup(s). Reported-by: Ephraim Park <ephiepark@fb.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <jolsa@redhat.com> Cc: <kernel-team@fb.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/20180312165943.1057894-1-songliubraving@fb.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-19Merge tag 'v4.16-rc6' into perf/core, to pick up fixesIngo Molnar1-1/+3
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-16perf/core: Clear sibling list of detached eventsMark Rutland1-1/+1
When perf_group_dettach() is called on a group leader, it updates each sibling's group_leader field to point to that sibling, effectively upgrading each siblnig to a group leader. After perf_group_detach has completed, the caller may free the leader event. We only remove siblings from the group leader's sibling_list when the leader has a non-empty group_node. This was fine prior to commit: 8343aae66167df67 ("perf/core: Remove perf_event::group_entry") ... as the sibling's sibling_list would be empty. However, now that we use the sibling_list field as both the list head and the list entry, this leaves each sibling with a non-empty sibling list, including the stale leader event. If perf_group_detach() is subsequently called on a sibling, it will appear to be a group leader, and we'll walk the sibling_list, potentially dereferencing these stale events. In 0day testing, this has been observed to result in kernel panics. Let's avoid this by always removing siblings from the sibling list when we promote them to leaders. Fixes: 8343aae66167df67 ("perf/core: Remove perf_event::group_entry") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: vincent.weaver@maine.edu Cc: Peter Zijlstra <peterz@infradead.org> Cc: torvalds@linux-foundation.org Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: valery.cherepennikov@intel.com Cc: linux-tip-commits@vger.kernel.org Cc: eranian@google.com Cc: acme@redhat.com Cc: alexander.shishkin@linux.intel.com Cc: davidcc@google.com Cc: kan.liang@intel.com Cc: Dmitry.Prohorov@intel.com Cc: Jiri Olsa <jolsa@redhat.com> Link: https://lkml.kernel.org/r/20180316131741.3svgr64yibc6vsid@lakrids.cambridge.arm.com
2018-03-16perf: Fix sibling iterationPeter Zijlstra1-18/+16
Mark noticed that the change to sibling_list changed some iteration semantics; because previously we used group_list as list entry, sibling events would always have an empty sibling_list. But because we now use sibling_list for both list head and list entry, siblings will report as having siblings. Fix this with a custom for_each_sibling_event() iterator. Fixes: 8343aae66167 ("perf/core: Remove perf_event::group_entry") Reported-by: Mark Rutland <mark.rutland@arm.com> Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: vincent.weaver@maine.edu Cc: alexander.shishkin@linux.intel.com Cc: torvalds@linux-foundation.org Cc: alexey.budankov@linux.intel.com Cc: valery.cherepennikov@intel.com Cc: eranian@google.com Cc: acme@redhat.com Cc: linux-tip-commits@vger.kernel.org Cc: davidcc@google.com Cc: kan.liang@intel.com Cc: Dmitry.Prohorov@intel.com Cc: jolsa@redhat.com Link: https://lkml.kernel.org/r/20180315170129.GX4043@hirez.programming.kicks-ass.net
2018-03-13perf/core: Implement fast breakpoint modification via _IOC_MODIFY_ATTRIBUTESMilind Chabbi2-1/+49
Problem and motivation: Once a breakpoint perf event (PERF_TYPE_BREAKPOINT) is created, there is no flexibility to change the breakpoint type (bp_type), breakpoint address (bp_addr), or breakpoint length (bp_len). The only option is to close the perf event and configure a new breakpoint event. This inflexibility has a significant performance overhead. For example, sampling-based, lightweight performance profilers (and also concurrency bug detection tools), monitor different addresses for a short duration using PERF_TYPE_BREAKPOINT and change the address (bp_addr) to another address or change the kind of breakpoint (bp_type) from "write" to a "read" or vice-versa or change the length (bp_len) of the address being monitored. The cost of these modifications is prohibitive since it involves unmapping the circular buffer associated with the perf event, closing the perf event, opening another perf event and mmaping another circular buffer. Solution: The new ioctl flag for perf events, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, introduced in this patch takes a pointer to a struct perf_event_attr as an argument to update an old breakpoint event with new address, type, and size. This facility allows retaining a previous mmaped perf events ring buffer and avoids having to close and reopen another perf event. This patch supports only changing PERF_TYPE_BREAKPOINT event type; future implementations can extend this feature. The patch replicates some of its functionality of modify_user_hw_breakpoint() in kernel/events/hw_breakpoint.c. modify_user_hw_breakpoint cannot be called directly since perf_event_ctx_lock() is already held in _perf_ioctl(). Evidence: Experiments show that the baseline (not able to modify an already created breakpoint) costs an order of magnitude (~10x) more than the suggested optimization (having the ability to dynamically modifying a configured breakpoint via ioctl). When the breakpoints typically do not trap, the speedup due to the suggested optimization is ~10x; even when the breakpoints always trap, the speedup is ~4x due to the suggested optimization. Testing: tests posted at https://github.com/linux-contrib/perf_event_modify_bp demonstrate the performance significance of this patch. Tests also check the functional correctness of the patch. Signed-off-by: Milind Chabbi <chabbi.milind@gmail.com> [ Using modify_user_hw_breakpoint_check function. ] [ Reformated PERF_EVENT_IOC_*, so the values are all in one column. ] Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oleg Nesterov <onestero@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20180312134548.31532-8-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-13perf/core: Move perf_event_attr::sample_max_stack into perf_copy_attr()Jiri Olsa1-3/+3
Move the sample_max_stack check and setup into perf_copy_attr(), so we have all perf_event_attr initial setup in one place and can easily compare attrs in the new ioctl introduced in following change. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Milind Chabbi <chabbi.milind@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oleg Nesterov <onestero@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20180312134548.31532-7-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-13hw_breakpoint: Add perf_event_attr fields check in __modify_user_hw_breakpoint()Jiri Olsa1-2/+7
And rename it to modify_user_hw_breakpoint_check(). We are about to use modify_user_hw_breakpoint_check() for user space breakpoints modification, we must be very strict to check only the fields we can change have changed. As Peter explained: "Suppose someone does: attr = malloc(sizeof(*attr)); // uninitialized memory attr->type = BP; attr->bp_addr = new_addr; attr->bp_type = bp_type; attr->bp_len = bp_len; ioctl(fd, PERF_IOC_MOD_ATTR, &attr); And feeds absolute shite for the rest of the fields. Then we later want to extend IOC_MOD_ATTR to allow changing attr::sample_type but we can't, because that would break the above application." I'm making this check optional because we already export modify_user_hw_breakpoint() and with this check we could break existing users. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Milind Chabbi <chabbi.milind@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oleg Nesterov <onestero@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20180312134548.31532-6-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-13hw_breakpoint: Factor out __modify_user_hw_breakpoint() functionJiri Olsa1-17/+29
Moving out all the functionality without the events disabling/enabling calls, because we want to call another disabling/enabling functions in following change. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Milind Chabbi <chabbi.milind@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oleg Nesterov <onestero@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20180312134548.31532-5-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-13hw_breakpoint: Add modify_bp_slot() functionJiri Olsa1-7/+39
Add the modify_bp_slot() function to keep slot numbers correct when changing the breakpoint type. Using existing __release_bp_slot()/__reserve_bp_slot() call sequence to update the slot counts. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Milind Chabbi <chabbi.milind@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oleg Nesterov <onestero@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20180312134548.31532-4-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-13hw_breakpoint: Pass bp_type argument to __reserve_bp_slot|__release_bp_slot()Jiri Olsa1-10/+10
Passing bp_type argument to __reserve_bp_slot() and __release_bp_slot() functions, so we can pass another bp_type than the one defined in bp->attr.bp_type. This will be handy in following change that fixes breakpoint slot counts during its modification. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Milind Chabbi <chabbi.milind@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oleg Nesterov <onestero@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20180312134548.31532-3-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-13hw_breakpoint: Pass bp_type directly as find_slot_idx() argumentJiri Olsa1-5/+5
Pass bp_type directly as a find_slot_idx() argument, so we don't need to have whole event to get the breakpoint slot type. It will be used in following changes. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Milind Chabbi <chabbi.milind@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oleg Nesterov <onestero@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20180312134548.31532-2-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12perf/core: Fix installing cgroup events on CPUleilei.lin1-11/+35
There's two problems when installing cgroup events on CPUs: firstly list_update_cgroup_event() only tries to set cpuctx->cgrp for the first event, if that mismatches on @cgrp we'll not try again for later additions. Secondly, when we install a cgroup event into an active context, only issue an event reprogram when the event matches the current cgroup context. This avoids a pointless event reprogramming. Signed-off-by: leilei.lin <leilei.lin@alibaba-inc.com> [ Improved the changelog and comments. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: brendan.d.gregg@gmail.com Cc: eranian@gmail.com Cc: linux-kernel@vger.kernel.org Cc: yang_oliver@hotmail.com Link: http://lkml.kernel.org/r/20180306093637.28247-1-linxiulei@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12perf/core: Optimize perf_rotate_context() event schedulingPeter Zijlstra1-23/+37
The event schedule order (as per perf_event_sched_in()) is: - cpu pinned - task pinned - cpu flexible - task flexible But perf_rotate_context() will unschedule cpu-flexible even if it doesn't need a rotation. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12perf/core: Fix tree based event rotationPeter Zijlstra1-26/+18
Similar to how first programming cpu=-1 and then cpu=# is wrong, so is rotating both. It was especially wrong when we were still programming the PMU in this same order, because in that scenario we might never actually end up running cpu=# events at all. Cure this by using the active_list to pick the rotation event; since at programming we already select the left-most event. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Carrillo-Cisneros <davidcc@google.com> Cc: Dmitri Prokhorov <Dmitry.Prohorov@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valery Cherepennikov <valery.cherepennikov@intel.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12perf/core: Simpify perf_event_groups_for_each()Peter Zijlstra1-7/+7
The last argument is, and always must be, the same. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Carrillo-Cisneros <davidcc@google.com> Cc: Dmitri Prokhorov <Dmitry.Prohorov@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valery Cherepennikov <valery.cherepennikov@intel.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12perf/core: Optimize ctx_sched_out()Peter Zijlstra1-24/+29
When an event group contains more events than can be scheduled on the hardware, iterating the full event group for ctx_sched_out is a waste of time. Keep track of the events that got programmed on the hardware, such that we can iterate this smaller list in order to schedule them out. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Carrillo-Cisneros <davidcc@google.com> Cc: Dmitri Prokhorov <Dmitry.Prohorov@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valery Cherepennikov <valery.cherepennikov@intel.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12perf/core: Remove perf_event::group_entryPeter Zijlstra1-19/+18
Now that all the grouping is done with RB trees, we no longer need group_entry and can replace the whole thing with sibling_list. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Carrillo-Cisneros <davidcc@google.com> Cc: Dmitri Prokhorov <Dmitry.Prohorov@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valery Cherepennikov <valery.cherepennikov@intel.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12perf/core: Fix event schedule orderPeter Zijlstra1-49/+108
Scheduling in events with cpu=-1 before events with cpu=# changes semantics and is undesirable in that it would priorize these events. Given that groups->index is across all groups we actually have an inter-group ordering, meaning we can merge-sort two groups, which is just what we need to preserve semantics. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Carrillo-Cisneros <davidcc@google.com> Cc: Dmitri Prokhorov <Dmitry.Prohorov@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valery Cherepennikov <valery.cherepennikov@intel.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12perf/core: Cleanup the rb-tree codePeter Zijlstra1-44/+40
Trivial comment and code fixups.. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Carrillo-Cisneros <davidcc@google.com> Cc: Dmitri Prokhorov <Dmitry.Prohorov@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valery Cherepennikov <valery.cherepennikov@intel.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12perf/cor: Use RB trees for pinned/flexible groupsAlexey Budankov1-53/+254
Change event groups into RB trees sorted by CPU and then by a 64bit index, so that multiplexing hrtimer interrupt handler would be able skipping to the current CPU's list and ignore groups allocated for the other CPUs. New API for manipulating event groups in the trees is implemented as well as adoption on the API in the current implementation. pinned_group_sched_in() and flexible_group_sched_in() API are introduced to consolidate code enabling the whole group from pinned and flexible groups appropriately. Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: David Carrillo-Cisneros <davidcc@google.com> Cc: Dmitri Prokhorov <Dmitry.Prohorov@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valery Cherepennikov <valery.cherepennikov@intel.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/372f9c8b-0cfe-4240-e44d-83d863d40813@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-12perf/core: Fix perf_output_read_group()Peter Zijlstra1-1/+2
Mark reported his arm64 perf fuzzer runs sometimes splat like: armv8pmu_read_counter+0x1e8/0x2d8 armpmu_event_update+0x8c/0x188 armpmu_read+0xc/0x18 perf_output_read+0x550/0x11e8 perf_event_read_event+0x1d0/0x248 perf_event_exit_task+0x468/0xbb8 do_exit+0x690/0x1310 do_group_exit+0xd0/0x2b0 get_signal+0x2e8/0x17a8 do_signal+0x144/0x4f8 do_notify_resume+0x148/0x1e8 work_pending+0x8/0x14 which asserts that we only call pmu::read() on ACTIVE events. The above callchain does: perf_event_exit_task() perf_event_exit_task_context() task_ctx_sched_out() // INACTIVE perf_event_exit_event() perf_event_set_state(EXIT) // EXIT sync_child_event() perf_event_read_event() perf_output_read() perf_output_read_group() leader->pmu->read() Which results in doing a pmu::read() on an !ACTIVE event. I _think_ this is 'new' since we added attr.inherit_stat, which added the perf_event_read_event() to the exit path, without that perf_event_read_output() would only trigger from samples and for @event to trigger a sample, it's leader _must_ be ACTIVE too. Still, adding this check makes it consistent with the @sub case for the siblings. Reported-and-Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-09perf/core: Fix ctx_event_type in ctx_resched()Song Liu1-1/+3
In ctx_resched(), EVENT_FLEXIBLE should be sched_out when EVENT_PINNED is added. However, ctx_resched() calculates ctx_event_type before checking this condition. As a result, pinned events will NOT get higher priority than flexible events. The following shows this issue on an Intel CPU (where ref-cycles can only use one hardware counter). 1. First start: perf stat -C 0 -e ref-cycles -I 1000 2. Then, in the second console, run: perf stat -C 0 -e ref-cycles:D -I 1000 The second perf uses pinned events, which is expected to have higher priority. However, because it failed in ctx_resched(). It is never run. This patch fixes this by calculating ctx_event_type after re-evaluating event_type. Reported-by: Ephraim Park <ephiepark@fb.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <jolsa@redhat.com> Cc: <kernel-team@fb.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Fixes: 487f05e18aa4 ("perf/core: Optimize event rescheduling on active contexts") Link: http://lkml.kernel.org/r/20180306055504.3283731-1-songliubraving@fb.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-17Merge branch 'perf/urgent' into perf/core, to pick up fixesIngo Molnar2-3/+14
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-12vfs: do bulk POLL* -> EPOLL* replacementLinus Torvalds2-2/+2
This is the mindless scripted replacement of kernel use of POLL* variables as described by Al, done by this script: for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'` for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done done with de-mangling cleanups yet to come. NOTE! On almost all architectures, the EPOLL* constants have the same values as the POLL* constants do. But they keyword here is "almost". For various bad reasons they aren't the same, and epoll() doesn't actually work quite correctly in some cases due to this on Sparc et al. The next patch from Al will sort out the final differences, and we should be all done. Scripted-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06perf/core: Implement the 'perf_uprobe' PMUSong Liu1-1/+47
This patch adds perf_uprobe support with similar pattern as previous patch (for kprobe). Two functions, create_local_trace_uprobe() and destroy_local_trace_uprobe(), are created so a uprobe can be created and attached to the file descriptor created by perf_event_open(). Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Yonghong Song <yhs@fb.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Cc: <daniel@iogearbox.net> Cc: <davem@davemloft.net> Cc: <kernel-team@fb.com> Cc: <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20171206224518.3598254-7-songliubraving@fb.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-06perf/core: Implement the 'perf_kprobe' PMUSong Liu1-35/+107
A new PMU type, perf_kprobe is added. Based on attr from perf_event_open(), perf_kprobe creates a kprobe (or kretprobe) for the perf_event. This kprobe is private to this perf_event, and thus not added to global lists, and not available in tracefs. Two functions, create_local_trace_kprobe() and destroy_local_trace_kprobe() are added to created and destroy these local trace_kprobe. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Yonghong Song <yhs@fb.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Cc: <daniel@iogearbox.net> Cc: <davem@davemloft.net> Cc: <kernel-team@fb.com> Cc: <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20171206224518.3598254-6-songliubraving@fb.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds1-0/+10
Pull networking updates from David Miller: 1) Significantly shrink the core networking routing structures. Result of http://vger.kernel.org/~davem/seoul2017_netdev_keynote.pdf 2) Add netdevsim driver for testing various offloads, from Jakub Kicinski. 3) Support cross-chip FDB operations in DSA, from Vivien Didelot. 4) Add a 2nd listener hash table for TCP, similar to what was done for UDP. From Martin KaFai Lau. 5) Add eBPF based queue selection to tun, from Jason Wang. 6) Lockless qdisc support, from John Fastabend. 7) SCTP stream interleave support, from Xin Long. 8) Smoother TCP receive autotuning, from Eric Dumazet. 9) Lots of erspan tunneling enhancements, from William Tu. 10) Add true function call support to BPF, from Alexei Starovoitov. 11) Add explicit support for GRO HW offloading, from Michael Chan. 12) Support extack generation in more netlink subsystems. From Alexander Aring, Quentin Monnet, and Jakub Kicinski. 13) Add 1000BaseX, flow control, and EEE support to mvneta driver. From Russell King. 14) Add flow table abstraction to netfilter, from Pablo Neira Ayuso. 15) Many improvements and simplifications to the NFP driver bpf JIT, from Jakub Kicinski. 16) Support for ipv6 non-equal cost multipath routing, from Ido Schimmel. 17) Add resource abstration to devlink, from Arkadi Sharshevsky. 18) Packet scheduler classifier shared filter block support, from Jiri Pirko. 19) Avoid locking in act_csum, from Davide Caratti. 20) devinet_ioctl() simplifications from Al viro. 21) More TCP bpf improvements from Lawrence Brakmo. 22) Add support for onlink ipv6 route flag, similar to ipv4, from David Ahern. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1925 commits) tls: Add support for encryption using async offload accelerator ip6mr: fix stale iterator net/sched: kconfig: Remove blank help texts openvswitch: meter: Use 64-bit arithmetic instead of 32-bit tcp_nv: fix potential integer overflow in tcpnv_acked r8169: fix RTL8168EP take too long to complete driver initialization. qmi_wwan: Add support for Quectel EP06 rtnetlink: enable IFLA_IF_NETNSID for RTM_NEWLINK ipmr: Fix ptrdiff_t print formatting ibmvnic: Wait for device response when changing MAC qlcnic: fix deadlock bug tcp: release sk_frag.page in tcp_disconnect ipv4: Get the address of interface correctly. net_sched: gen_estimator: fix lockdep splat net: macb: Handle HRESP error net/mlx5e: IPoIB, Fix copy-paste bug in flow steering refactoring ipv6: addrconf: break critical section in addrconf_verify_rtnl() ipv6: change route cache aging logic i40e/i40evf: Update DESC_NEEDED value to reflect larger value bnxt_en: cleanup DIM work on device shutdown ...
2018-01-31Merge branch 'misc.poll' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull poll annotations from Al Viro: "This introduces a __bitwise type for POLL### bitmap, and propagates the annotations through the tree. Most of that stuff is as simple as 'make ->poll() instances return __poll_t and do the same to local variables used to hold the future return value'. Some of the obvious brainos found in process are fixed (e.g. POLLIN misspelled as POLL_IN). At that point the amount of sparse warnings is low and most of them are for genuine bugs - e.g. ->poll() instance deciding to return -EINVAL instead of a bitmap. I hadn't touched those in this series - it's large enough as it is. Another problem it has caught was eventpoll() ABI mess; select.c and eventpoll.c assumed that corresponding POLL### and EPOLL### were equal. That's true for some, but not all of them - EPOLL### are arch-independent, but POLL### are not. The last commit in this series separates userland POLL### values from the (now arch-independent) kernel-side ones, converting between them in the few places where they are copied to/from userland. AFAICS, this is the least disruptive fix preserving poll(2) ABI and making epoll() work on all architectures. As it is, it's simply broken on sparc - try to give it EPOLLWRNORM and it will trigger only on what would've triggered EPOLLWRBAND on other architectures. EPOLLWRBAND and EPOLLRDHUP, OTOH, are never triggered at all on sparc. With this patch they should work consistently on all architectures" * 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits) make kernel-side POLL... arch-independent eventpoll: no need to mask the result of epi_item_poll() again eventpoll: constify struct epoll_event pointers debugging printk in sg_poll() uses %x to print POLL... bitmap annotate poll(2) guts 9p: untangle ->poll() mess ->si_band gets POLL... bitmap stored into a user-visible long field ring_buffer_poll_wait() return value used as return value of ->poll() the rest of drivers/*: annotate ->poll() instances media: annotate ->poll() instances fs: annotate ->poll() instances ipc, kernel, mm: annotate ->poll() instances net: annotate ->poll() instances apparmor: annotate ->poll() instances tomoyo: annotate ->poll() instances sound: annotate ->poll() instances acpi: annotate ->poll() instances crypto: annotate ->poll() instances block: annotate ->poll() instances x86: annotate ->poll() instances ...
2018-01-31Merge tag 'arm64-upstream' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Catalin Marinas: "The main theme of this pull request is security covering variants 2 and 3 for arm64. I expect to send additional patches next week covering an improved firmware interface (requires firmware changes) for variant 2 and way for KPTI to be disabled on unaffected CPUs (Cavium's ThunderX doesn't work properly with KPTI enabled because of a hardware erratum). Summary: - Security mitigations: - variant 2: invalidate the branch predictor with a call to secure firmware - variant 3: implement KPTI for arm64 - 52-bit physical address support for arm64 (ARMv8.2) - arm64 support for RAS (firmware first only) and SDEI (software delegated exception interface; allows firmware to inject a RAS error into the OS) - perf support for the ARM DynamIQ Shared Unit PMU - CPUID and HWCAP bits updated for new floating point multiplication instructions in ARMv8.4 - remove some virtual memory layout printks during boot - fix initial page table creation to cope with larger than 32M kernel images when 16K pages are enabled" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (104 commits) arm64: Fix TTBR + PAN + 52-bit PA logic in cpu_do_switch_mm arm64: Turn on KPTI only on CPUs that need it arm64: Branch predictor hardening for Cavium ThunderX2 arm64: Run enable method for errata work arounds on late CPUs arm64: Move BP hardening to check_and_switch_context arm64: mm: ignore memory above supported physical address size arm64: kpti: Fix the interaction between ASID switching and software PAN KVM: arm64: Emulate RAS error registers and set HCR_EL2's TERR & TEA KVM: arm64: Handle RAS SErrors from EL2 on guest exit KVM: arm64: Handle RAS SErrors from EL1 on guest exit KVM: arm64: Save ESR_EL2 on guest SError KVM: arm64: Save/Restore guest DISR_EL1 KVM: arm64: Set an impdef ESR for Virtual-SError using VSESR_EL2. KVM: arm/arm64: mask/unmask daif around VHE guests arm64: kernel: Prepare for a DISR user arm64: Unconditionally enable IESB on exception entry/return for firmware-first arm64: kernel: Survive corrected RAS errors notified by SError arm64: cpufeature: Detect CPU RAS Extentions arm64: sysreg: Move to use definitions for all the SCTLR bits arm64: cpufeature: __this_cpu_has_cap() shouldn't stop early ...
2018-01-30Merge branch 'perf-core-for-linus' of ↵Linus Torvalds3-34/+39
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf updates from Ingo Molnar: "Kernel side changes: - Clean up the x86 instruction decoder (Masami Hiramatsu) - Add new uprobes optimization for PUSH instructions on x86 (Yonghong Song) - Add MSR_IA32_THERM_STATUS to the MSR events (Stephane Eranian) - Fix misc bugs, update documentation, plus various cleanups (Jiri Olsa) There's a large number of tooling side improvements: - Intel-PT/BTS improvements (Adrian Hunter) - Numerous 'perf trace' improvements (Arnaldo Carvalho de Melo) - Introduce an errno code to string facility (Hendrik Brueckner) - Various build system improvements (Jiri Olsa) - Add support for CoreSight trace decoding by making the perf tools use the external openCSD (Mathieu Poirier, Tor Jeremiassen) - Add ARM Statistical Profiling Extensions (SPE) support (Kim Phillips) - libtraceevent updates (Steven Rostedt) - Intel vendor event JSON updates (Andi Kleen) - Introduce 'perf report --mmaps' and 'perf report --tasks' to show info present in 'perf.data' (Jiri Olsa, Arnaldo Carvalho de Melo) - Add infrastructure to record first and last sample time to the perf.data file header, so that when processing all samples in a 'perf record' session, such as when doing build-id processing, or when specifically requesting that that info be recorded, use that in 'perf report --time', that also got support for percent slices in addition to absolute ones. I.e. now it is possible to ask for the samples in the 10%-20% time slice of a perf.data file (Jin Yao) - Allow system wide 'perf stat --per-thread', sorting the result (Jin Yao) E.g.: [root@jouet ~]# perf stat --per-thread --metrics IPC ^C Performance counter stats for 'system wide': make-22229 23,012,094,032 inst_retired.any # 0.8 IPC cc1-22419 692,027,497 inst_retired.any # 0.8 IPC gcc-22418 328,231,855 inst_retired.any # 0.9 IPC cc1-22509 220,853,647 inst_retired.any # 0.8 IPC gcc-22486 199,874,810 inst_retired.any # 1.0 IPC as-22466 177,896,365 inst_retired.any # 0.9 IPC cc1-22465 150,732,374 inst_retired.any # 0.8 IPC gcc-22508 112,555,593 inst_retired.any # 0.9 IPC cc1-22487 108,964,079 inst_retired.any # 0.7 IPC qemu-system-x86-2697 21,330,550 inst_retired.any # 0.3 IPC systemd-journal-551 20,642,951 inst_retired.any # 0.4 IPC docker-containe-17651 9,552,892 inst_retired.any # 0.5 IPC dockerd-current-9809 7,528,586 inst_retired.any # 0.5 IPC make-22153 12,504,194,380 inst_retired.any # 0.8 IPC python2-22429 12,081,290,954 inst_retired.any # 0.8 IPC <SNIP> python2-22429 15,026,328,103 cpu_clk_unhalted.thread cc1-22419 826,660,193 cpu_clk_unhalted.thread gcc-22418 365,321,295 cpu_clk_unhalted.thread cc1-22509 279,169,362 cpu_clk_unhalted.thread gcc-22486 210,156,950 cpu_clk_unhalted.thread <SNIP> 5.638075538 seconds time elapsed [root@jouet ~]# - Improve shell auto-completion of perf events (Jin Yao) - 'perf probe' improvements (Masami Hiramatsu) - Improve PMU infrastructure to support amp64's ThunderX2 implementation defined core events (Ganapatrao Kulkarni) - Various annotation related improvements and fixes (Thomas Richter) - Clarify usage of 'overwrite' and 'backward' in the evlist/mmap code, removing the 'overwrite' parameter from several functions as it was always used it as 'false' (Wang Nan) - Fix/improve 'perf record' reverse recording support (Wang Nan) - Improve command line options documentation (Sihyeon Jang) - Optimize sample parsing for ordering events, where we don't need to parse all the PERF_SAMPLE_ bits, just the ones leading to the timestamp needed to reorder events (Jiri Olsa) - Generalize the annotation code to support other source information besides objdump/DWARF obtained ones, starting with python scripts, that will is slated to be merged soon (Jiri Olsa) - ... and a lot more that I failed to list, see the shortlog and changelog for details" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (262 commits) perf trace beauty flock: Move to separate object file perf evlist: Remove fcntl.h from evlist.h perf trace beauty futex: Beautify FUTEX_BITSET_MATCH_ANY perf trace: Do not print from time delta for interrupted syscall lines perf trace: Add --print-sample perf bpf: Remove misplaced __maybe_unused attribute MAINTAINERS: Adding entry for CoreSight trace decoding perf tools: Add mechanic to synthesise CoreSight trace packets perf tools: Add full support for CoreSight trace decoding pert tools: Add queue management functionality perf tools: Add functionality to communicate with the openCSD decoder perf tools: Add support for decoding CoreSight trace data perf tools: Add decoder mechanic to support dumping trace data perf tools: Add processing of coresight metadata perf tools: Add initial entry point for decoder CoreSight traces perf tools: Integrating the CoreSight decoding library perf vendor events intel: Update IvyTown files to V20 perf vendor events intel: Update IvyBridge files to V20 perf vendor events intel: Update BroadwellDE events to V7 perf vendor events intel: Update SkylakeX events to V1.06 ...
2018-01-30Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds1-6/+6
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "The main RCU changes in this cycle were: - Updates to use cond_resched() instead of cond_resched_rcu_qs() where feasible (currently everywhere except in kernel/rcu and in kernel/torture.c). Also a couple of fixes to avoid sending IPIs to offline CPUs. - Updates to simplify RCU's dyntick-idle handling. - Updates to remove almost all uses of smp_read_barrier_depends() and read_barrier_depends(). - Torture-test updates. - Miscellaneous fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits) torture: Save a line in stutter_wait(): while -> for torture: Eliminate torture_runnable and perf_runnable torture: Make stutter less vulnerable to compilers and races locking/locktorture: Fix num reader/writer corner cases locking/locktorture: Fix rwsem reader_delay torture: Place all torture-test modules in one MAINTAINERS group rcutorture/kvm-build.sh: Skip build directory check rcutorture: Simplify functions.sh include path rcutorture: Simplify logging rcutorture/kvm-recheck-*: Improve result directory readability check rcutorture/kvm.sh: Support execution from any directory rcutorture/kvm.sh: Use consistent help text for --qemu-args rcutorture/kvm.sh: Remove unused variable, `alldone` rcutorture: Remove unused script, config2frag.sh rcutorture/configinit: Fix build directory error message rcutorture: Preempt RCU-preempt readers more vigorously torture: Reduce #ifdefs for preempt_schedule() rcu: Remove have_rcu_nocb_mask from tree_plugin.h rcu: Add comment giving debug strategy for double call_rcu() tracing, rcu: Hide trace event rcu_nocb_wake when not used ...
2018-01-25perf/core: Fix ctx::mutex deadlockPeter Zijlstra1-1/+7
Lockdep noticed the following 3-way lockup scenario: sys_perf_event_open() perf_event_alloc() perf_try_init_event() #0 ctx = perf_event_ctx_lock_nested(1) perf_swevent_init() swevent_hlist_get() #1 mutex_lock(&pmus_lock) perf_event_init_cpu() #1 mutex_lock(&pmus_lock) #2 mutex_lock(&ctx->mutex) sys_perf_event_open() mutex_lock_double() #2 mutex_lock() #0 mutex_lock_nested() And while we need that perf_event_ctx_lock_nested() for HW PMUs such that they can iterate the sibling list, trying to match it to the available counters, the software PMUs need do no such thing. Exclude them. In particular the swevent triggers the above invertion, while the tpevent PMU triggers a more elaborate one through their event_mutex. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-25perf/core: Fix another perf,trace,cpuhp lock inversionPeter Zijlstra1-2/+24
Lockdep noticed the following 3-way lockup race: perf_trace_init() #0 mutex_lock(&event_mutex) perf_trace_event_init() perf_trace_event_reg() tp_event->class->reg() := tracepoint_probe_register #1 mutex_lock(&tracepoints_mutex) trace_point_add_func() #2 static_key_enable() #2 do_cpu_up() perf_event_init_cpu() #3 mutex_lock(&pmus_lock) #4 mutex_lock(&ctx->mutex) perf_ioctl() #4 ctx = perf_event_ctx_lock() _perf_iotcl() ftrace_profile_set_filter() #0 mutex_lock(&event_mutex) Fudge it for now by noting that the tracepoint state does not depend on the event <-> context relation. Ugly though :/ Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-25perf/core: Fix lock inversion between perf,trace,cpuhpPeter Zijlstra1-2/+11
Lockdep gifted us with noticing the following 4-way lockup scenario: perf_trace_init() #0 mutex_lock(&event_mutex) perf_trace_event_init() perf_trace_event_reg() tp_event->class->reg() := tracepoint_probe_register #1 mutex_lock(&tracepoints_mutex) trace_point_add_func() #2 static_key_enable() #2 do_cpu_up() perf_event_init_cpu() #3 mutex_lock(&pmus_lock) #4 mutex_lock(&ctx->mutex) perf_event_task_disable() mutex_lock(&current->perf_event_mutex) #4 ctx = perf_event_ctx_lock() #5 perf_event_for_each_child() do_exit() task_work_run() __fput() perf_release() perf_event_release_kernel() #4 mutex_lock(&ctx->mutex) #5 mutex_lock(&event->child_mutex) free_event() _free_event() event->destroy() := perf_trace_destroy #0 mutex_lock(&event_mutex); Fix that by moving the free_event() out from under the locks. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-08perf: Return empty callchain instead of NULLJiri Olsa1-18/+12
It simplifies the code a bit, because we dump the callchain Link: http://lkml.kernel.org/n/tip-uqp7qd6aif47g39glnbu95yl@git.kernel.org even if it's empty. With 'empty' callchain we can remove all the NULL-checking code paths. Original-patch-from: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/20180107160356.28203-7-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-01-08perf: Make perf_callchain function staticJiri Olsa3-19/+16
And move it to core.c, because there's no caller of this function other than the one in core.c Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180107160356.28203-6-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-01-08perf: Allocate context task_ctx_data for child eventJiri Olsa1-0/+14
Currently we use perf_event_context::task_ctx_data to save and restore the LBR status when the task is scheduled out and in. We don't allocate it for child contexts, which results in shorter task's LBR stack, because we don't save the history from previous run and start over every time we schedule the task in. I made a test to generate samples with LBR call stack and got higher numbers on bigger chain depths: before: after: LBR call chain: nr: 1 60561 498127 LBR call chain: nr: 2 0 0 LBR call chain: nr: 3 107030 2172 LBR call chain: nr: 4 466685 62758 LBR call chain: nr: 5 2307319 878046 LBR call chain: nr: 6 48713 495218 LBR call chain: nr: 7 1040 4551 LBR call chain: nr: 8 481 172 LBR call chain: nr: 9 878 120 LBR call chain: nr: 10 2377 6698 LBR call chain: nr: 11 28830 151487 LBR call chain: nr: 12 29347 339867 LBR call chain: nr: 13 4 22 LBR call chain: nr: 14 3 53 Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Fixes: 4af57ef28c2c ("perf: Add pmu specific data for perf task context") Link: http://lkml.kernel.org/r/20180107160356.28203-4-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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