diff options
| author | Oleg Nesterov <oleg@tv-sign.ru> | 2008-02-01 17:29:05 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2008-02-10 10:48:03 +0100 |
| commit | 080344b98805553f9b01de0f59a41b1533036d8d (patch) | |
| tree | df56b37cca4b0ce233967682526158b58fa151b9 /include/linux | |
| parent | e13a2e61dd5152f5499d2003470acf9c838eab84 (diff) | |
hrtimer: fix *rmtp handling in hrtimer_nanosleep()
Spotted by Pavel Emelyanov and Alexey Dobriyan.
hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to
the local variable which lives in the caller's stack frame. This means that
if sys_restart_syscall() actually happens and it is interrupted as well, we
don't update the user-space variable, but write into the already dead stack
frame.
Introduced by commit 04c227140fed77587432667a574b14736a06dd7f
hrtimer: Rework hrtimer_nanosleep to make sys_compat_nanosleep easier
Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change
hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp.
Small problem remains. man 2 nanosleep states that *rtmp should be written if
nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp
if nanosleep returns 0), but (with or without this patch) we can dirty *rem
even if nanosleep() returns 0.
NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other
bugs. Fixed by the next patch.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Pavel Emelyanov <xemul@sw.ru>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Toyo Abe <toyoa@mvista.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
include/linux/hrtimer.h | 2 -
kernel/hrtimer.c | 51 +++++++++++++++++++++++++-----------------------
kernel/posix-timers.c | 14 +------------
3 files changed, 30 insertions(+), 37 deletions(-)
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/hrtimer.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 600fc3bcf63..1ad56a7b2f7 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -316,7 +316,7 @@ static inline u64 hrtimer_forward_now(struct hrtimer *timer, /* Precise sleep: */ extern long hrtimer_nanosleep(struct timespec *rqtp, - struct timespec *rmtp, + struct timespec __user *rmtp, const enum hrtimer_mode mode, const clockid_t clockid); extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); |