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authorMasami Hiramatsu <mhiramat@kernel.org>2018-06-20 01:16:17 +0900
committerIngo Molnar <mingo@kernel.org>2018-06-21 12:33:20 +0200
commit2bbda764d720aacabaad38374d26fcccb7843f17 (patch)
tree25d60c92825b75c73362b455baafb5464aca07cc /Documentation/kprobes.txt
parentcce188bd58cfbd603b904dbce75f34de2eff959a (diff)
downloadlinux-2bbda764d720aacabaad38374d26fcccb7843f17.tar.bz2
kprobes/x86: Do not disable preempt on int3 path
Since int3 and debug exception(for singlestep) are run with IRQ disabled and while running single stepping we drop IF from regs->flags, that path must not be preemptible. So we can remove the preempt disable/enable calls from that path. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Link: https://lore.kernel.org/lkml/152942497779.15209.2879580696589868291.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/kprobes.txt')
-rw-r--r--Documentation/kprobes.txt11
1 files changed, 5 insertions, 6 deletions
diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt
index ab2c7307f123..cbb545910634 100644
--- a/Documentation/kprobes.txt
+++ b/Documentation/kprobes.txt
@@ -566,12 +566,11 @@ the same handler) may run concurrently on different CPUs.
Kprobes does not use mutexes or allocate memory except during
registration and unregistration.
-Probe handlers are run with preemption disabled. Depending on the
-architecture and optimization state, handlers may also run with
-interrupts disabled (e.g., kretprobe handlers and optimized kprobe
-handlers run without interrupt disabled on x86/x86-64). In any case,
-your handler should not yield the CPU (e.g., by attempting to acquire
-a semaphore).
+Probe handlers are run with preemption disabled or interrupt disabled,
+which depends on the architecture and optimization state. (e.g.,
+kretprobe handlers and optimized kprobe handlers run without interrupt
+disabled on x86/x86-64). In any case, your handler should not yield
+the CPU (e.g., by attempting to acquire a semaphore, or waiting I/O).
Since a return probe is implemented by replacing the return
address with the trampoline's address, stack backtraces and calls