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| author | Jeff Dike <jdike@addtoit.com> | 2006-07-10 04:45:11 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-10 13:24:24 -0700 |
| commit | 61232f2fe44f7ac12d7512d099a8f10923eff7ea (patch) | |
| tree | f1f17d310daf7f5b60ad6713a7a1ac7011ae45e8 /arch/um/os-Linux/sigio.c | |
| parent | 8e64d96aeb495709c13307e2d79f3ee37e96aa4e (diff) | |
| download | lwn-61232f2fe44f7ac12d7512d099a8f10923eff7ea.tar.gz lwn-61232f2fe44f7ac12d7512d099a8f10923eff7ea.zip | |
[PATCH] uml: fix exitcall ordering bug
This fixes an exitcall ordering bug - calls to ignore_sigio_fd can come from
exitcalls that come after the sigio thread has been killed. This would cause
shutdown to hang or crash.
Fixed by having ignore_sigio_fd check that the thread is present before trying
to communicate with it.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/um/os-Linux/sigio.c')
| -rw-r--r-- | arch/um/os-Linux/sigio.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c index 0d2422a7d72c..d22623e8fced 100644 --- a/arch/um/os-Linux/sigio.c +++ b/arch/um/os-Linux/sigio.c @@ -191,6 +191,13 @@ int ignore_sigio_fd(int fd) struct pollfd *p; int err = 0, i, n = 0; + /* This is called from exitcalls elsewhere in UML - if + * sigio_cleanup has already run, then update_thread will hang + * or fail because the thread is no longer running. + */ + if(write_sigio_pid == -1) + return -EIO; + sigio_lock(); for(i = 0; i < current_poll.used; i++){ if(current_poll.poll[i].fd == fd) break; @@ -215,7 +222,7 @@ int ignore_sigio_fd(int fd) update_thread(); out: sigio_unlock(); - return(err); + return err; } static struct pollfd *setup_initial_poll(int fd) |