On Mon, Aug 7, 2023 at 10:34 AM Vlastimil Babka <vbabka@xxxxxxx> wrote: > > On a laptop with hibernation set up but not actively used, and with > secure boot and lockdown enabled kernel, 6.5-rc1 gets stuck on boot with > the following repeated messages: > > A start job is running for Resume from hibernation using device /dev/system/swap (24s / no limit) > lockdown_is_locked_down: 25311154 callbacks suppressed > Lockdown: systemd-hiberna: hibernation is restricted; see man kernel_lockdown.7 > ... > > Checking the resume code leads to commit cc89c63e2fe3 ("PM: hibernate: > move finding the resume device out of software_resume") which > inadvertently changed the return value from resume_store() to 0 when > !hibernation_available(). This apparently translates to userspace > write() returning 0 as in number of bytes written, and userspace looping > indefinitely in the attempt to write the intended value. > > Fix this by returning the full number of bytes that were to be written, > as that's what was done before the commit. > > Fixes: cc89c63e2fe3 ("PM: hibernate: move finding the resume device out of software_resume") > Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> > Reviewed-by: Christoph Hellwig <hch@xxxxxx> > Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > --- > Resend with review/ack tags added and not buried in the thread. > Link: https://lore.kernel.org/all/2cfa5f55-1d68-8a4f-d049-13f42e0d1484@xxxxxxx/ > > kernel/power/hibernate.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c > index e1b4bfa938dd..2b4a946a6ff5 100644 > --- a/kernel/power/hibernate.c > +++ b/kernel/power/hibernate.c > @@ -1166,7 +1166,7 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr, > int error; > > if (!hibernation_available()) > - return 0; > + return n; > > if (len && buf[len-1] == '\n') > len--; > -- Applied as 6.5-rc material, thanks!