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author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-24 16:16:55 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-24 16:16:55 -0700 |
commit | 44744bb344abe032b387d361209038d2956e8c75 (patch) | |
tree | e5b4eec5a313c9ee9b7b0f22ce3ba77970ea17e0 /kernel | |
parent | 959dc2587d69f77af9de63199bd2dc468a736595 (diff) | |
parent | b3f207855f57b9c8f43a547a801340bb5cbc59e5 (diff) | |
download | op-kernel-dev-44744bb344abe032b387d361209038d2956e8c75.zip op-kernel-dev-44744bb344abe032b387d361209038d2956e8c75.tar.gz |
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"A kprobes and a perf compat ioctl fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Handle compat ioctl
kprobes: Skip kretprobe hit in NMI context to avoid deadlock
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/events/core.c | 23 | ||||
-rw-r--r-- | kernel/kprobes.c | 13 |
2 files changed, 34 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 1cf24b3..f9c1ed0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -41,6 +41,7 @@ #include <linux/cgroup.h> #include <linux/module.h> #include <linux/mman.h> +#include <linux/compat.h> #include "internal.h" @@ -3717,6 +3718,26 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) return 0; } +#ifdef CONFIG_COMPAT +static long perf_compat_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + switch (_IOC_NR(cmd)) { + case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): + case _IOC_NR(PERF_EVENT_IOC_ID): + /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ + if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { + cmd &= ~IOCSIZE_MASK; + cmd |= sizeof(void *) << IOCSIZE_SHIFT; + } + break; + } + return perf_ioctl(file, cmd, arg); +} +#else +# define perf_compat_ioctl NULL +#endif + int perf_event_task_enable(void) { struct perf_event *event; @@ -4222,7 +4243,7 @@ static const struct file_operations perf_fops = { .read = perf_read, .poll = perf_poll, .unlocked_ioctl = perf_ioctl, - .compat_ioctl = perf_ioctl, + .compat_ioctl = perf_compat_ioctl, .mmap = perf_mmap, .fasync = perf_fasync, }; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 734e9a7..3995f54 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1778,7 +1778,18 @@ static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) unsigned long hash, flags = 0; struct kretprobe_instance *ri; - /*TODO: consider to only swap the RA after the last pre_handler fired */ + /* + * To avoid deadlocks, prohibit return probing in NMI contexts, + * just skip the probe and increase the (inexact) 'nmissed' + * statistical counter, so that the user is informed that + * something happened: + */ + if (unlikely(in_nmi())) { + rp->nmissed++; + return 0; + } + + /* TODO: consider to only swap the RA after the last pre_handler fired */ hash = hash_ptr(current, KPROBE_HASH_BITS); raw_spin_lock_irqsave(&rp->lock, flags); if (!hlist_empty(&rp->free_instances)) { |