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author | Bodo Stroesser <bstroesser@fujitsu-siemens.com> | 2005-09-03 22:57:24 (GMT) |
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committer | Linus Torvalds <torvalds@evo.osdl.org> | 2005-09-05 07:06:21 (GMT) |
commit | ed1b58d8b53519e10a35c6a2bb49cac35f439621 (patch) | |
tree | 30eacf51f9e7d11fcfe2c795e3da48e1e7363daf | |
parent | 0221575903ad68debea57679b5b46575bf57afb1 (diff) | |
download | linux-fsl-qoriq-ed1b58d8b53519e10a35c6a2bb49cac35f439621.tar.xz |
[PATCH] uml: fix SIGWINCH handler race while waiting for signals.
If a SIGWINCH comes in, while winch_thread() isn't waiting in wait(),
winch_thread could miss signals. It isn't very probable, that anyone will
see this causing trouble, as it would need a very special timing, that a
missed SIGWINCH results in a wrong window size.
So, this is a minor problem. But why not fix, as it can be done so easy?
Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r-- | arch/um/drivers/chan_user.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c index 5d37681..de3bce7 100644 --- a/arch/um/drivers/chan_user.c +++ b/arch/um/drivers/chan_user.c @@ -63,7 +63,7 @@ error: * * SIGWINCH can't be received synchronously, so you have to set up to receive it * as a signal. That being the case, if you are going to wait for it, it is - * convenient to sit in a pause() and wait for the signal to bounce you out of + * convenient to sit in sigsuspend() and wait for the signal to bounce you out of * it (see below for how we make sure to exit only on SIGWINCH). */ @@ -94,18 +94,19 @@ static int winch_thread(void *arg) "byte, err = %d\n", -count); /* We are not using SIG_IGN on purpose, so don't fix it as I thought to - * do! If using SIG_IGN, the pause() call below would not stop on + * do! If using SIG_IGN, the sigsuspend() call below would not stop on * SIGWINCH. */ signal(SIGWINCH, winch_handler); sigfillset(&sigs); - sigdelset(&sigs, SIGWINCH); - /* Block anything else than SIGWINCH. */ + /* Block all signals possible. */ if(sigprocmask(SIG_SETMASK, &sigs, NULL) < 0){ printk("winch_thread : sigprocmask failed, errno = %d\n", errno); exit(1); } + /* In sigsuspend(), block anything else than SIGWINCH. */ + sigdelset(&sigs, SIGWINCH); if(setsid() < 0){ printk("winch_thread : setsid failed, errno = %d\n", errno); @@ -130,7 +131,7 @@ static int winch_thread(void *arg) while(1){ /* This will be interrupted by SIGWINCH only, since other signals * are blocked.*/ - pause(); + sigsuspend(&sigs); count = os_write_file(pipe_fd, &c, sizeof(c)); if(count != sizeof(c)) |