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authorLinus Torvalds <torvalds@linux-foundation.org>2017-06-10 20:15:47 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-06-10 20:15:47 +0300
commitf701d860af381265639244fb84b07797fbb5efca (patch)
treea434e40ab7ee6c41cb2248d9c0fc7f54653a8c68 /kernel
parent9376906c17fa975bf6a7ea9dd124be697bcda289 (diff)
parent47c1ded7fef108c730b803cd386241beffcdd15c (diff)
downloadlinux-f701d860af381265639244fb84b07797fbb5efca.tar.xz
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar: "This is mostly tooling fixes, plus an instruction pointer filtering fix. It's more fixes than usual - Arnaldo got back from a longer vacation and there was a backlog" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits) perf symbols: Kill dso__build_id_is_kmod() perf symbols: Keep DSO->symtab_type after decompress perf tests: Decompress kernel module before objdump perf tools: Consolidate error path in __open_dso() perf tools: Decompress kernel module when reading DSO data perf annotate: Use dso__decompress_kmodule_path() perf tools: Introduce dso__decompress_kmodule_{fd,path} perf tools: Fix a memory leak in __open_dso() perf annotate: Fix symbolic link of build-id cache perf/core: Drop kernel samples even though :u is specified perf script python: Remove dups in documentation examples perf script python: Updated trace_unhandled() signature perf script python: Fix wrong code snippets in documentation perf script: Fix documentation errors perf script: Fix outdated comment for perf-trace-python perf probe: Fix examples section of documentation perf report: Ensure the perf DSO mapping matches what libdw sees perf report: Include partial stacks unwound with libdw perf annotate: Add missing powerpc triplet perf test: Disable breakpoint signal tests for powerpc ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 6e75a5c9412d..6c4e523dc1e2 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7316,6 +7316,21 @@ int perf_event_account_interrupt(struct perf_event *event)
return __perf_event_account_interrupt(event, 1);
}
+static bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs)
+{
+ /*
+ * Due to interrupt latency (AKA "skid"), we may enter the
+ * kernel before taking an overflow, even if the PMU is only
+ * counting user events.
+ * To avoid leaking information to userspace, we must always
+ * reject kernel samples when exclude_kernel is set.
+ */
+ if (event->attr.exclude_kernel && !user_mode(regs))
+ return false;
+
+ return true;
+}
+
/*
* Generic event overflow handling, sampling.
*/
@@ -7337,6 +7352,12 @@ static int __perf_event_overflow(struct perf_event *event,
ret = __perf_event_account_interrupt(event, throttle);
/*
+ * For security, drop the skid kernel samples if necessary.
+ */
+ if (!sample_is_allowed(event, regs))
+ return ret;
+
+ /*
* XXX event_limit might not quite work as expected on inherited
* events
*/