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author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-11-30 11:31:48 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-11-30 11:31:48 -0800 |
commit | a1b3cf6d943800059adc262c4d839524c529db2d (patch) | |
tree | a8bdf99464f0b971dcbebf90d06af8072f218939 /kernel | |
parent | 8d9f412d51b84eafd2253a82120e218ddc53e721 (diff) | |
parent | 09d3f015d1e1b4fee7e9bbdcf54201d239393391 (diff) | |
download | linux-stable-a1b3cf6d943800059adc262c4d839524c529db2d.tar.gz linux-stable-a1b3cf6d943800059adc262c4d839524c529db2d.tar.bz2 linux-stable-a1b3cf6d943800059adc262c4d839524c529db2d.zip |
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"Misc fixes:
- counter freezing related regression fix
- uprobes race fix
- Intel PMU unusual event combination fix
- .. and diverse tooling fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
uprobes: Fix handle_swbp() vs. unregister() + register() race once more
perf/x86/intel: Disallow precise_ip on BTS events
perf/x86/intel: Add generic branch tracing check to intel_pmu_has_bts()
perf/x86/intel: Move branch tracing setup to the Intel-specific source file
perf/x86/intel: Fix regression by default disabling perfmon v4 interrupt handling
perf tools beauty ioctl: Support new ISO7816 commands
tools uapi asm-generic: Synchronize ioctls.h
tools arch x86: Update tools's copy of cpufeatures.h
tools headers uapi: Synchronize i915_drm.h
perf tools: Restore proper cwd on return from mnt namespace
tools build feature: Check if get_current_dir_name() is available
perf tools: Fix crash on synthesizing the unit
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/events/uprobes.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 96d4bee83489..322e97bbb437 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -829,7 +829,7 @@ static int prepare_uprobe(struct uprobe *uprobe, struct file *file, BUG_ON((uprobe->offset & ~PAGE_MASK) + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); - smp_wmb(); /* pairs with rmb() in find_active_uprobe() */ + smp_wmb(); /* pairs with the smp_rmb() in handle_swbp() */ set_bit(UPROBE_COPY_INSN, &uprobe->flags); out: @@ -2178,10 +2178,18 @@ static void handle_swbp(struct pt_regs *regs) * After we hit the bp, _unregister + _register can install the * new and not-yet-analyzed uprobe at the same address, restart. */ - smp_rmb(); /* pairs with wmb() in install_breakpoint() */ if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags))) goto out; + /* + * Pairs with the smp_wmb() in prepare_uprobe(). + * + * Guarantees that if we see the UPROBE_COPY_INSN bit set, then + * we must also see the stores to &uprobe->arch performed by the + * prepare_uprobe() call. + */ + smp_rmb(); + /* Tracing handlers use ->utask to communicate with fetch methods */ if (!get_utask()) goto out; |