From: Qiujun Huang <hqjagain@xxxxxxxxx>
commit 99b3b837855b987563bcfb397cf9ddd88262814b upstream.
There is a case found when triggering a panic_on_oom, pstore fails to dump
kmsg. Because psz_kmsg_write_record can't get the new buffer.
Handle this by using GFP_ATOMIC to allocate a buffer at lower watermark.
Signed-off-by: Qiujun Huang <hqjagain@xxxxxxxxx>
Fixes: 335426c6dcdd ("pstore/zone: Provide way to skip "broken" zone for MTD devices")
Cc: WeiXiong Liao <gmpy.liaowx@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/CAJRQjofRCF7wjrYmw3D7zd5QZnwHQq+F8U-mJDJ6NZ4bddYdLA@xxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/pstore/zone.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/pstore/zone.c
+++ b/fs/pstore/zone.c
@@ -761,7 +761,7 @@ static inline int notrace psz_kmsg_write
/* avoid destroying old data, allocate a new one */
len = zone->buffer_size + sizeof(*zone->buffer);
zone->oldbuf = zone->buffer;
- zone->buffer = kzalloc(len, GFP_KERNEL);
+ zone->buffer = kzalloc(len, GFP_ATOMIC);
if (!zone->buffer) {
zone->buffer = zone->oldbuf;
return -ENOMEM;
