diff options
author | Wang YanQing <[email protected]> | 2013-01-26 15:53:57 +0800 |
---|---|---|
committer | Ingo Molnar <[email protected]> | 2013-01-28 11:21:57 +0100 |
commit | f44310b98ddb7f0d06550d73ed67df5865e3eda5 (patch) | |
tree | 77696b4312a7450afcc24c478df4721eda2f777f /net/lapb | |
parent | c903f0456bc69176912dee6dd25c6a66ee1aed00 (diff) |
smp: Fix SMP function call empty cpu mask race
I get the following warning every day with v3.7, once or
twice a day:
[ 2235.186027] WARNING: at /mnt/sda7/kernel/linux/arch/x86/kernel/apic/ipi.c:109 default_send_IPI_mask_logical+0x2f/0xb8()
As explained by Linus as well:
|
| Once we've done the "list_add_rcu()" to add it to the
| queue, we can have (another) IPI to the target CPU that can
| now see it and clear the mask.
|
| So by the time we get to actually send the IPI, the mask might
| have been cleared by another IPI.
|
This patch also fixes a system hang problem, if the data->cpumask
gets cleared after passing this point:
if (WARN_ONCE(!mask, "empty IPI mask"))
return;
then the problem in commit 83d349f35e1a ("x86: don't send an IPI to
the empty set of CPU's") will happen again.
Signed-off-by: Wang YanQing <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Acked-by: Jan Beulich <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: <[email protected]>
Link: http://lkml.kernel.org/r/20130126075357.GA3205@udknight
[ Tidied up the changelog and the comment in the code. ]
Signed-off-by: Ingo Molnar <[email protected]>
Diffstat (limited to 'net/lapb')
0 files changed, 0 insertions, 0 deletions