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| author | Waiman Long <longman@redhat.com> | 2024-08-06 19:46:47 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-08-08 03:33:56 +0200 |
| commit | 6d45e1c948a8b7ed6ceddb14319af69424db730c (patch) | |
| tree | 5837f0700a8dfe5a647e5aad295a433b5183698a /kernel/padata.c | |
| parent | mailmap: update entry for David Heidelberg (diff) | |
| download | linux-6d45e1c948a8b7ed6ceddb14319af69424db730c.tar.xz linux-6d45e1c948a8b7ed6ceddb14319af69424db730c.zip | |
padata: Fix possible divide-by-0 panic in padata_mt_helper()
We are hit with a not easily reproducible divide-by-0 panic in padata.c at
bootup time.
[ 10.017908] Oops: divide error: 0000 1 PREEMPT SMP NOPTI
[ 10.017908] CPU: 26 PID: 2627 Comm: kworker/u1666:1 Not tainted 6.10.0-15.el10.x86_64 #1
[ 10.017908] Hardware name: Lenovo ThinkSystem SR950 [7X12CTO1WW]/[7X12CTO1WW], BIOS [PSE140J-2.30] 07/20/2021
[ 10.017908] Workqueue: events_unbound padata_mt_helper
[ 10.017908] RIP: 0010:padata_mt_helper+0x39/0xb0
:
[ 10.017963] Call Trace:
[ 10.017968] <TASK>
[ 10.018004] ? padata_mt_helper+0x39/0xb0
[ 10.018084] process_one_work+0x174/0x330
[ 10.018093] worker_thread+0x266/0x3a0
[ 10.018111] kthread+0xcf/0x100
[ 10.018124] ret_from_fork+0x31/0x50
[ 10.018138] ret_from_fork_asm+0x1a/0x30
[ 10.018147] </TASK>
Looking at the padata_mt_helper() function, the only way a divide-by-0
panic can happen is when ps->chunk_size is 0. The way that chunk_size is
initialized in padata_do_multithreaded(), chunk_size can be 0 when the
min_chunk in the passed-in padata_mt_job structure is 0.
Fix this divide-by-0 panic by making sure that chunk_size will be at least
1 no matter what the input parameters are.
Link: https://lkml.kernel.org/r/20240806174647.1050398-1-longman@redhat.com
Fixes: 004ed42638f4 ("padata: add basic support for multithreaded jobs")
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Waiman Long <longman@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to '')
| -rw-r--r-- | kernel/padata.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/padata.c b/kernel/padata.c index 53f4bc912712..0fa6c2895460 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -517,6 +517,13 @@ void __init padata_do_multithreaded(struct padata_mt_job *job) ps.chunk_size = max(ps.chunk_size, job->min_chunk); ps.chunk_size = roundup(ps.chunk_size, job->align); + /* + * chunk_size can be 0 if the caller sets min_chunk to 0. So force it + * to at least 1 to prevent divide-by-0 panic in padata_mt_helper().` + */ + if (!ps.chunk_size) + ps.chunk_size = 1U; + list_for_each_entry(pw, &works, pw_list) if (job->numa_aware) { int old_node = atomic_read(&last_used_nid); |