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authorJeff Dike <jdike@addtoit.com>2006-07-10 04:45:11 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-10 13:24:24 -0700
commit61232f2fe44f7ac12d7512d099a8f10923eff7ea (patch)
treef1f17d310daf7f5b60ad6713a7a1ac7011ae45e8 /arch/um
parent8e64d96aeb495709c13307e2d79f3ee37e96aa4e (diff)
downloadop-kernel-dev-61232f2fe44f7ac12d7512d099a8f10923eff7ea.zip
op-kernel-dev-61232f2fe44f7ac12d7512d099a8f10923eff7ea.tar.gz
[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')
-rw-r--r--arch/um/os-Linux/sigio.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 0d2422a..d22623e 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)
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