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| author |   Al Viro <viro@zeniv.linux.org.uk> | 2012-04-30 18:24:46 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-06-01 13:01:51 -0400 |
| commit | 44fbbb3dc687c9709a6f2236197316e5c79ab1eb (patch) | |
| tree | d3c995b1cb7e3f9ac5af09b8d78f6c839a65f35a /arch/x86/kernel/signal.c | |
| parent | blackfin: check __get_user() return value (diff) | |
| download | linux-dev-44fbbb3dc687c9709a6f2236197316e5c79ab1eb.tar.xz linux-dev-44fbbb3dc687c9709a6f2236197316e5c79ab1eb.zip | |
x86: get rid of calling do_notify_resume() when returning to kernel mode
If we end up calling do_notify_resume() with !user_mode(refs), it
does nothing (do_signal() explicitly bails out and we can't get there
with TIF_NOTIFY_RESUME in such situations). Then we jump to
resume_userspace_sig, which rechecks the same thing and bails out
to resume_kernel, thus breaking the loop.
It's easier and cheaper to check *before* calling do_notify_resume()
and bail out to resume_kernel immediately. And kill the check in
do_signal()...
Note that on amd64 we can't get there with !user_mode() at all - asm
glue takes care of that.
Acked-and-reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/x86/kernel/signal.c')
| -rw-r--r-- | arch/x86/kernel/signal.c | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index e8a89374d356..21af737053aa 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -737,16 +737,6 @@ static void do_signal(struct pt_regs *regs) siginfo_t info; int signr; - /* - * We want the common case to go fast, which is why we may in certain - * cases get here from kernel mode. Just return without doing anything - * if so. - * X86_32: vm86 regs switched out by assembly code before reaching - * here, so testing against kernel CS suffices. - */ - if (!user_mode(regs)) - return; - signr = get_signal_to_deliver(&info, &ka, regs, NULL); if (signr > 0) { /* Whee! Actually deliver the signal. */ |