* [PATCH] pstore/zone: Use GFP_ATOMIC to allocate zone buffer
@ 2022-09-04 15:17 Qiujun Huang
2022-09-06 20:18 ` Kees Cook
0 siblings, 1 reply; 2+ messages in thread
From: Qiujun Huang @ 2022-09-04 15:17 UTC (permalink / raw)
To: keescook, anton, ccross, tony.luck, LKML
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@gmail.com>
---
fs/pstore/zone.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/pstore/zone.c b/fs/pstore/zone.c
index 017d0d4ad329..2770746bb7aa 100644
--- a/fs/pstore/zone.c
+++ b/fs/pstore/zone.c
@@ -761,7 +761,7 @@ static inline int notrace
psz_kmsg_write_record(struct psz_context *cxt,
/* 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;
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] pstore/zone: Use GFP_ATOMIC to allocate zone buffer
2022-09-04 15:17 [PATCH] pstore/zone: Use GFP_ATOMIC to allocate zone buffer Qiujun Huang
@ 2022-09-06 20:18 ` Kees Cook
0 siblings, 0 replies; 2+ messages in thread
From: Kees Cook @ 2022-09-06 20:18 UTC (permalink / raw)
To: Qiujun Huang; +Cc: WeiXiong Liao, anton, ccross, tony.luck, LKML
On Sun, Sep 04, 2022 at 11:17:13PM +0800, Qiujun Huang wrote:
> 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@gmail.com>
> ---
> fs/pstore/zone.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/pstore/zone.c b/fs/pstore/zone.c
> index 017d0d4ad329..2770746bb7aa 100644
> --- a/fs/pstore/zone.c
> +++ b/fs/pstore/zone.c
> @@ -761,7 +761,7 @@ static inline int notrace
> psz_kmsg_write_record(struct psz_context *cxt,
> /* 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;
This patch appears to be whitespace damaged, but I've manually applied
it. Thank you!
https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?h=for-next/pstore&id=27001e611bb642287eddf93227bd72d295a35453
--
Kees Cook
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2022-09-06 20:20 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-09-04 15:17 [PATCH] pstore/zone: Use GFP_ATOMIC to allocate zone buffer Qiujun Huang
2022-09-06 20:18 ` Kees Cook
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).