6.12-stable review patch. If anyone has any objections, please let me know.
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From: Milan Broz gmazyland@gmail.com
commit 7fb39882b20c98a9a393c244c86b56ef6933cff8 upstream.
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+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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); }