user/sven/linux.git/kernel/events, branch v5.4.61

uprobes: __replace_page() avoid BUG in munlock_vma_page()

2020-08-26T08:40:51Z

commit c17c3dc9d08b9aad9a55a1e53f205187972f448e upstream. syzbot crashed on the VM_BUG_ON_PAGE(PageTail) in munlock_vma_page(), when called from uprobes __replace_page(). Which of many ways to fix it? Settled on not calling when PageCompound (since Head and Tail are equals in this context, PageCompound the usual check in uprobes.c, and the prior use of FOLL_SPLIT_PMD will have cleared PageMlocked already). Fixes: 5a52c9df62b4 ("uprobe: use FOLL_SPLIT_PMD instead of FOLL_SPLIT") Reported-by: syzbot Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Reviewed-by: Srikar Dronamraju Acked-by: Song Liu Acked-by: Oleg Nesterov Cc: "Kirill A. Shutemov" Cc: [5.4+] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008161338360.20413@eggly.anvils Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

perf/core: Fix endless multiplex timer

2020-08-11T13:33:32Z

commit 90c91dfb86d0ff545bd329d3ddd72c147e2ae198 upstream. Kan and Andi reported that we fail to kill rotation when the flexible events go empty, but the context does not. XXX moar Fixes: fd7d55172d1e ("perf/cgroups: Don't rotate events for cgroups unnecessarily") Reported-by: Andi Kleen Reported-by: Kan Liang Tested-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200305123851.GX2596@hirez.programming.kicks-ass.net Cc: Robin Murphy Signed-off-by: Greg Kroah-Hartman

uprobes: Change handle_swbp() to send SIGTRAP with si_code=SI_KERNEL, to fix GDB regression

2020-07-29T08:18:29Z

commit fe5ed7ab99c656bd2f5b79b49df0e9ebf2cead8a upstream. If a tracee is uprobed and it hits int3 inserted by debugger, handle_swbp() does send_sig(SIGTRAP, current, 0) which means si_code == SI_USER. This used to work when this code was written, but then GDB started to validate si_code and now it simply can't use breakpoints if the tracee has an active uprobe: # cat test.c void unused_func(void) { } int main(void) { return 0; } # gcc -g test.c -o test # perf probe -x ./test -a unused_func # perf record -e probe_test:unused_func gdb ./test -ex run GNU gdb (GDB) 10.0.50.20200714-git ... Program received signal SIGTRAP, Trace/breakpoint trap. 0x00007ffff7ddf909 in dl_main () from /lib64/ld-linux-x86-64.so.2 (gdb) The tracee hits the internal breakpoint inserted by GDB to monitor shared library events but GDB misinterprets this SIGTRAP and reports a signal. Change handle_swbp() to use force_sig(SIGTRAP), this matches do_int3_user() and fixes the problem. This is the minimal fix for -stable, arch/x86/kernel/uprobes.c is equally wrong; it should use send_sigtrap(TRAP_TRACE) instead of send_sig(SIGTRAP), but this doesn't confuse GDB and needs another x86-specific patch. Reported-by: Aaron Merey Signed-off-by: Oleg Nesterov Signed-off-by: Ingo Molnar Reviewed-by: Srikar Dronamraju Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200723154420.GA32043@redhat.com Signed-off-by: Greg Kroah-Hartman

perf: Add cond_resched() to task_function_call()

2020-06-17T14:40:36Z

commit 2ed6edd33a214bca02bd2b45e3fc3038a059436b upstream. Under rare circumstances, task_function_call() can repeatedly fail and cause a soft lockup. There is a slight race where the process is no longer running on the cpu we targeted by the time remote_function() runs. The code will simply try again. If we are very unlucky, this will continue to fail, until a watchdog fires. This can happen in a heavily loaded, multi-core virtual machine. Reported-by: syzbot+bb4935a5c09b5ff79940@syzkaller.appspotmail.com Signed-off-by: Barret Rhoden Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200414222920.121401-1-brho@google.com Signed-off-by: Greg Kroah-Hartman

uprobes: ensure that uprobe->offset and ->ref_ctr_offset are properly aligned

2020-06-10T18:24:58Z

commit 013b2deba9a6b80ca02f4fafd7dedf875e9b4450 upstream. uprobe_write_opcode() must not cross page boundary; prepare_uprobe() relies on arch_uprobe_analyze_insn() which should validate "vaddr" but some architectures (csky, s390, and sparc) don't do this. We can remove the BUG_ON() check in prepare_uprobe() and validate the offset early in __uprobe_register(). The new IS_ALIGNED() check matches the alignment check in arch_prepare_kprobe() on supported architectures, so I think that all insns must be aligned to UPROBE_SWBP_INSN_SIZE. Another problem is __update_ref_ctr() which was wrong from the very beginning, it can read/write outside of kmap'ed page unless "vaddr" is aligned to sizeof(short), __uprobe_register() should check this too. Reported-by: Linus Torvalds Suggested-by: Linus Torvalds Signed-off-by: Oleg Nesterov Reviewed-by: Srikar Dronamraju Acked-by: Christian Borntraeger Tested-by: Sven Schnelle Cc: Steven Rostedt Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

perf/core: fix parent pid/tid in task exit events

2020-05-02T06:48:52Z

commit f3bed55e850926614b9898fe982f66d2541a36a5 upstream. Current logic yields the child task as the parent. Before: $ perf record bash -c "perf list > /dev/null" $ perf script -D |grep 'FORK\|EXIT' 4387036190981094 0x5a70 [0x30]: PERF_RECORD_FORK(10472:10472):(10470:10470) 4387036606207580 0xf050 [0x30]: PERF_RECORD_EXIT(10472:10472):(10472:10472) 4387036607103839 0x17150 [0x30]: PERF_RECORD_EXIT(10470:10470):(10470:10470) ^ Note the repeated values here -------------------/ After: 383281514043 0x9d8 [0x30]: PERF_RECORD_FORK(2268:2268):(2266:2266) 383442003996 0x2180 [0x30]: PERF_RECORD_EXIT(2268:2268):(2266:2266) 383451297778 0xb70 [0x30]: PERF_RECORD_EXIT(2266:2266):(2265:2265) Fixes: 94d5d1b2d891 ("perf_counter: Report the cloning task as parent on perf_counter_fork()") Reported-by: KP Singh Signed-off-by: Ian Rogers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200417182842.12522-1-irogers@google.com Signed-off-by: Greg Kroah-Hartman

perf/core: Disable page faults when getting phys address

2020-04-29T14:33:02Z

[ Upstream commit d3296fb372bf7497b0e5d0478c4e7a677ec6f6e9 ] We hit following warning when running tests on kernel compiled with CONFIG_DEBUG_ATOMIC_SLEEP=y: WARNING: CPU: 19 PID: 4472 at mm/gup.c:2381 __get_user_pages_fast+0x1a4/0x200 CPU: 19 PID: 4472 Comm: dummy Not tainted 5.6.0-rc6+ #3 RIP: 0010:__get_user_pages_fast+0x1a4/0x200 ... Call Trace: perf_prepare_sample+0xff1/0x1d90 perf_event_output_forward+0xe8/0x210 __perf_event_overflow+0x11a/0x310 __intel_pmu_pebs_event+0x657/0x850 intel_pmu_drain_pebs_nhm+0x7de/0x11d0 handle_pmi_common+0x1b2/0x650 intel_pmu_handle_irq+0x17b/0x370 perf_event_nmi_handler+0x40/0x60 nmi_handle+0x192/0x590 default_do_nmi+0x6d/0x150 do_nmi+0x2f9/0x3c0 nmi+0x8e/0xd7 While __get_user_pages_fast() is IRQ-safe, it calls access_ok(), which warns on: WARN_ON_ONCE(!in_task() && !pagefault_disabled()) Peter suggested disabling page faults around __get_user_pages_fast(), which gets rid of the warning in access_ok() call. Suggested-by: Peter Zijlstra Signed-off-by: Jiri Olsa Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/20200407141427.3184722-1-jolsa@kernel.org Signed-off-by: Sasha Levin

perf/core: Fix mlock accounting in perf_mmap()

2020-02-11T12:35:54Z

commit 003461559ef7a9bd0239bae35a22ad8924d6e9ad upstream. Decreasing sysctl_perf_event_mlock between two consecutive perf_mmap()s of a perf ring buffer may lead to an integer underflow in locked memory accounting. This may lead to the undesired behaviors, such as failures in BPF map creation. Address this by adjusting the accounting logic to take into account the possibility that the amount of already locked memory may exceed the current limit. Fixes: c4b75479741c ("perf/core: Make the mlock accounting simple again") Suggested-by: Alexander Shishkin Signed-off-by: Song Liu Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: Acked-by: Alexander Shishkin Link: https://lkml.kernel.org/r/20200123181146.2238074-1-songliubraving@fb.com Signed-off-by: Greg Kroah-Hartman

perf: Correctly handle failed perf_get_aux_event()

2020-01-23T07:22:33Z

commit da9ec3d3dd0f1240a48920be063448a2242dbd90 upstream. Vince reports a worrying issue: | so I was tracking down some odd behavior in the perf_fuzzer which turns | out to be because perf_even_open() sometimes returns 0 (indicating a file | descriptor of 0) even though as far as I can tell stdin is still open. ... and further the cause: | error is triggered if aux_sample_size has non-zero value. | | seems to be this line in kernel/events/core.c: | | if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) | goto err_locked; | | (note, err is never set) This seems to be a thinko in commit: ab43762ef010967e ("perf: Allow normal events to output AUX data") ... and we should probably return -EINVAL here, as this should only happen when the new event is mis-configured or does not have a compatible aux_event group leader. Fixes: ab43762ef010967e ("perf: Allow normal events to output AUX data") Reported-by: Vince Weaver Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Acked-by: Alexander Shishkin Tested-by: Vince Weaver Signed-off-by: Greg Kroah-Hartman

perf/core: Fix the mlock accounting, again

2019-12-31T15:45:38Z

[ Upstream commit 36b3db03b4741b8935b68fffc7e69951d8d70a89 ] Commit: 5e6c3c7b1ec2 ("perf/aux: Fix tracking of auxiliary trace buffer allocation") tried to guess the correct combination of arithmetic operations that would undo the AUX buffer's mlock accounting, and failed, leaking the bottom part when an allocation needs to be charged partially to both user->locked_vm and mm->pinned_vm, eventually leaving the user with no locked bonus: $ perf record -e intel_pt//u -m1,128 uname [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.061 MB perf.data ] $ perf record -e intel_pt//u -m1,128 uname Permission error mapping pages. Consider increasing /proc/sys/kernel/perf_event_mlock_kb, or try again with a smaller value of -m/--mmap_pages. (current value: 1,128) Fix this by subtracting both locked and pinned counts when AUX buffer is unmapped. Reported-by: Thomas Richter Tested-by: Thomas Richter Signed-off-by: Alexander Shishkin Acked-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mark Rutland Cc: Namhyung Kim Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin