2023-07-11 11:53:45

by Azat Khuzhin

Subject: [PATCH] Fix writing maj:min to /sys/power/resume (fixes hiberation with systemd)

resume_store() first calls lookup_bdev() and after tries to handle
maj:min, but it does not reset the error before, hence if you will write
maj:min you will get ENOENT:

# echo 259:2 >| /sys/power/resume
bash: echo: write error: No such file or directory

This also should fix hiberation via systemd, since it uses this way.

Fixes: 1e8c813b083c4 ("PM: hibernate: don't use early_lookup_bdev in resume_store")
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Azat Khuzhin <[email protected]>
---
kernel/power/hibernate.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index f62e89d0d906..e1b4bfa938dd 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -1179,6 +1179,7 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
unsigned maj, min, offset;
char *p, dummy;

+ error = 0;
if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 ||
sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset,
&dummy) == 3) {
--
2.41.0

2023-07-11 12:19:23

by Christoph Hellwig

Subject: Re: [PATCH] Fix writing maj:min to /sys/power/resume (fixes hiberation with systemd)

On Tue, Jul 11, 2023 at 01:48:12PM +0200, Azat Khuzhin wrote:
> resume_store() first calls lookup_bdev() and after tries to handle
> maj:min, but it does not reset the error before, hence if you will write
> maj:min you will get ENOENT:
>
> # echo 259:2 >| /sys/power/resume
> bash: echo: write error: No such file or directory
>
> This also should fix hiberation via systemd, since it uses this way.

Looks good:

Reviewed-by: Christoph Hellwig <[email protected]>

2023-07-11 18:54:40

by Rafael J. Wysocki

Subject: Re: [PATCH] Fix writing maj:min to /sys/power/resume (fixes hiberation with systemd)

On Tue, Jul 11, 2023 at 2:08 PM Christoph Hellwig <[email protected]> wrote:
>
> On Tue, Jul 11, 2023 at 01:48:12PM +0200, Azat Khuzhin wrote:
> > resume_store() first calls lookup_bdev() and after tries to handle
> > maj:min, but it does not reset the error before, hence if you will write
> > maj:min you will get ENOENT:
> >
> > # echo 259:2 >| /sys/power/resume
> > bash: echo: write error: No such file or directory
> >
> > This also should fix hiberation via systemd, since it uses this way.
>
> Looks good:
>
> Reviewed-by: Christoph Hellwig <[email protected]>

Applied as 6.5-rc material, thanks!