The patch titled
uml: fix exitcall ordering bug
has been added to the -mm tree. Its filename is
uml-fix-exitcall-ordering-bug.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: uml: fix exitcall ordering bug
From: Jeff Dike <jdike@xxxxxxxxxxx>
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@xxxxxxxxxxx>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/um/os-Linux/sigio.c | 9 ++++++++-
1 files changed, 8 insertions(+), 1 deletion(-)
diff -puN arch/um/os-Linux/sigio.c~uml-fix-exitcall-ordering-bug arch/um/os-Linux/sigio.c
--- a/arch/um/os-Linux/sigio.c~uml-fix-exitcall-ordering-bug
+++ a/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)
_
Patches currently in -mm which might be from jdike@xxxxxxxxxxx are
uml-clean-up-address-space-limits-code.patch
uml-timer-initialization-cleanup.patch
uml-remove-some-useless-exports.patch
uml-fix-static-binary-segfault.patch
uml-remove-useless-declaration.patch
uml-signal-initialization-cleanup.patch
uml-timer-handler-tidying.patch
uml-ifdef-a-mode-specific-function.patch
uml-mark-forward_interrupts-as-being-mode-specific.patch
uml-remove-spinlock-wrapper-functions.patch
uml-remove-os_isatty.patch
uml-fix-exitcall-ordering-bug.patch
uml-make-some-symbols-static.patch
uml-remove-syscall-debugging.patch
uml-move-_kernc-files.patch
uml-formatting-fixes.patch
uml-add-some-eintr-protection.patch
uml-remove-unused-variable.patch
uml-make-mconsole-version-requests-happen-in-a-process.patch
uml-remove-pte_mkexec.patch
-
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