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 <gmazyl...@gmail.com>
Fixes: fb0987682c62 ("dm-integrity: introduce the Inline mode")
Cc: sta...@vger.kernel.org # 6.11+
---
drivers/md/dm-integrity.c | 8 ++++----
1 file 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);
}
--
2.47.2
