stop_machine: fix race with return value (fixes Bug #11989)

PATCH In review Rusty Russell 2 participants 2 messages Nov 16, 2008 – Nov 17, 2008

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Rusty Russell

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2008-11-16 21:52 UTC #0 lore raw

PATCH 1/1 stop_machine: fix race with return value (fixes Bug #11989)

Bug #11989: Suspend failure on NForce4-based boards due to chanes in stop_machine
We should not access active.fnret outside the lock; in theory the nextstop_machine could overwrite it.

Signed-off-by Rusty Russell <[email protected]>Tested-by: "Rafael J. Wysocki" <[email protected]>--- kernel/stop_machine.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff -r d7c9a15da615 kernel/stop_machine.c--- a/kernel/stop_machine.c Mon Nov 10 09:47:45 2008 +1100+++ b/kernel/stop_machine.c Tue Nov 11 23:19:47 2008 +1030@@ -112,7 +112,7 @@ int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus) { struct work_struct *sm_work;- int i;+ int i, ret; /* Set up initial state. */ mutex_lock(&lock);@@ -137,8 +137,9 @@ /* This will release the thread on our CPU. */ put_cpu(); flush_workqueue(stop_machine_wq);+ ret = active.fnret; mutex_unlock(&lock);- return active.fnret;+ return ret; } int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)��{.n�+��+%��ݶ��w��{.n�+��{��G��{ay�ʇڙ�,j��f��h��z_�(�階�ݢj"��m��G��?��&��~��iO��z��v�^�m��?�I�

Heiko Carstens

2008-11-17 09:46 UTC #1 lore raw

Quoted 10 lines · Rusty Russell

Bug #11989: Suspend failure on NForce4-based boards due to chanes in stop_machine
We should not access active.fnret outside the lock; in theory the next stop_machine could overwrite it.
Signed-off-by Rusty Russell <[email protected]>
Tested-by "Rafael J. Wysocki" <[email protected]>
---
 kernel/stop_machine.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Thank you, Rusty, for finding and fixing this one as well!