| Message ID | 20250110102821.2a37581b@fangorn (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | fs/proc: fix softlockup in __read_vmcore (part 2) | expand |
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 3d8a82cee63e..658bf199d424 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -404,6 +404,8 @@ static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos) if (!iov_iter_count(iter)) return acc; } + + cond_resched(); } return acc;
Since commit 5cbcb62dddf5 ("fs/proc: fix softlockup in __read_vmcore") the number of softlockups in __read_vmcore at kdump time have gone down, but they still happen sometimes. In a memory constrained environment like the kdump image, a softlockup is not just a harmless message, but it can interfere with things like RCU freeing memory, causing the crashdump to get stuck. The second loop in __read_vmcore has a lot more opportunities for natural sleep points, like scheduling out while waiting for a data write to happen, but apparently that is not always enough. Add a cond_resched() to the second loop in __read_vmcore to (hopefully) get rid of the softlockups. Signed-off-by: Rik van Riel <riel@surriel.com> Fixes: 5cbcb62dddf5 ("fs/proc: fix softlockup in __read_vmcore") Reported-by: Breno Leitao <leitao@debian.org> --- fs/proc/vmcore.c | 2 ++ 1 file changed, 2 insertions(+)