On Fri, 2020-11-13 at 20:10 +0800, kernel test robot wrote:
> Greeting,
>
> FYI, we noticed the following commit (built with gcc-9):
>
> commit: b6efe2fcc4e11010710ef5cd8e2bcbeb221a06c6 ("mm: slub: Convert sysfs sprintf family to sysfs_emit/sysfs_emit_at")
> url: https://github.com/0day-ci/linux/commits/Joe-Perches/mm-Convert-sysfs-sprintf-family-to-sysfs_emit/20201102-041456
[]
> on test machine: 8 threads Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz with 32G memory
>
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
>
> If you fix the issue, kindly add following tag
> Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
>
> [ 41.689368] BUG: kernel NULL pointer dereference, address: 0000000000000010
> [ 41.696354] #PF: supervisor read access in kernel mode
> [ 41.701508] #PF: error_code(0x0000) - not-present page
> [ 41.706661] PGD 0 P4D 0
> [ 41.709205] Oops: 0000 [#1] SMP PTI
> [ 41.712702] CPU: 3 PID: 4619 Comm: read_all Tainted: G I 5.10.0-rc1-00005-gb6efe2fcc4e1 #1
> [ 41.722296] Hardware name: Dell Inc. OptiPlex 7050/062KRH, BIOS 1.2.0 12/22/2016
> [ 41.729714] RIP: 0010:slabs_cpu_partial_show+0x95/0xe0
Right, thanks.
I mistakenly dropped a test for page below:
@@ -5156,44 +5156,45 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
- if (page && len < PAGE_SIZE - 20)
- len += sprintf(buf + len, " C%d=%d(%d)", cpu,
- page->pobjects, page->pages);
+ len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
+ cpu, page->pobjects, page->pages);
}
I'll correct it and resubmit.
