/* * bpf-script-test-prologue.c * Test BPF prologue */ #ifndef LINUX_VERSION_CODE # error Need LINUX_VERSION_CODE # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig' #endif #define SEC(NAME) __attribute__((section(NAME), used)) #include #define FMODE_READ 0x1 #define FMODE_WRITE 0x2 static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) = (void *) 6; SEC("func=null_lseek file->f_mode offset orig") int bpf_func__null_lseek(void *ctx, int err, unsigned long f_mode, unsigned long offset, unsigned long orig) { if (err) return 0; if (f_mode & FMODE_WRITE) return 0; if (offset & 1) return 0; if (orig == SEEK_CUR) return 0; return 1; } char _license[] SEC("license") = "GPL"; int _version SEC("version") = LINUX_VERSION_CODE; ss='form'>
net-next plumbingsTobias Klauser
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authorPeter Zijlstra <peterz@infradead.org>2017-01-26 16:39:55 +0100
committerIngo Molnar <mingo@kernel.org>2017-01-30 11:41:25 +0100
commita76a82a3e38c8d3fb6499e3dfaeb0949241ab588 (patch)
treeb5bc906278fe1ac66d75de984d26bf59b43b3ed8 /tools/objtool/special.c
parent566cf877a1fcb6d6dc0126b076aad062054c2637 (diff)
perf/core: Fix use-after-free bug
Dmitry reported a KASAN use-after-free on event->group_leader. It turns out there's a hole in perf_remove_from_context() due to event_function_call() not calling its function when the task associated with the event is already dead. In this case the event will have been detached from the task, but the grouping will have been retained, such that group operations might still work properly while there are live child events etc. This does however mean that we can miss a perf_group_detach() call when the group decomposes, this in turn can then lead to use-after-free. Fix it by explicitly doing the group detach if its still required. Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org # v4.5+ Cc: syzkaller <syzkaller@googlegroups.com> Fixes: 63b6da39bb38 ("perf: Fix perf_event_exit_task() race") Link: http://lkml.kernel.org/r/20170126153955.GD6515@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools/objtool/special.c')