diff options
| author | Milan Broz <gmazyland@gmail.com> | 2025-02-16 11:42:09 +0100 |
|---|---|---|
| committer | Mikulas Patocka <mpatocka@redhat.com> | 2025-02-17 11:33:07 +0100 |
| commit | 7fb39882b20c98a9a393c244c86b56ef6933cff8 (patch) | |
| tree | 3e86a3d1a4ad6d726cce2a3bb32f28a860209d76 | |
| parent | 0ad2507d5d93f39619fc42372c347d6006b64319 (diff) | |
dm-integrity: Avoid divide by zero in table status in Inline mode
In Inline mode, the journal is unused, and journal_sectors is zero.
Calculating the journal watermark requires dividing by journal_sectors,
which should be done only if the journal is configured.
Otherwise, a simple table query (dmsetup table) can cause OOPS.
This bug did not show on some systems, perhaps only due to
compiler optimization.
On my 32-bit testing machine, this reliably crashes with the following:
: Oops: divide error: 0000 [#1] PREEMPT SMP
: CPU: 0 UID: 0 PID: 2450 Comm: dmsetup Not tainted 6.14.0-rc2+ #959
: EIP: dm_integrity_status+0x2f8/0xab0 [dm_integrity]
...
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: fb0987682c62 ("dm-integrity: introduce the Inline mode")
Cc: stable@vger.kernel.org # 6.11+
| -rw-r--r-- | drivers/md/dm-integrity.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c index ee9f7cecd78e..555dc06b9422 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -3790,10 +3790,6 @@ static void dm_integrity_status(struct dm_target *ti, status_type_t type, break; case STATUSTYPE_TABLE: { - __u64 watermark_percentage = (__u64)(ic->journal_entries - ic->free_sectors_threshold) * 100; - - watermark_percentage += ic->journal_entries / 2; - do_div(watermark_percentage, ic->journal_entries); arg_count = 3; arg_count += !!ic->meta_dev; arg_count += ic->sectors_per_block != 1; @@ -3826,6 +3822,10 @@ static void dm_integrity_status(struct dm_target *ti, status_type_t type, DMEMIT(" interleave_sectors:%u", 1U << ic->sb->log2_interleave_sectors); DMEMIT(" buffer_sectors:%u", 1U << ic->log2_buffer_sectors); if (ic->mode == 'J') { + __u64 watermark_percentage = (__u64)(ic->journal_entries - ic->free_sectors_threshold) * 100; + + watermark_percentage += ic->journal_entries / 2; + do_div(watermark_percentage, ic->journal_entries); DMEMIT(" journal_watermark:%u", (unsigned int)watermark_percentage); DMEMIT(" commit_time:%u", ic->autocommit_msec); } |