From: Håkon Bugge Date: Wed, 2 Jul 2025 09:10:34 +0000 (+0200) Subject: md/md-bitmap: fix GPF in bitmap_get_stats() X-Git-Tag: v6.16-rc6~12^2~2^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c17fb542dbd1db745c9feac15617056506dd7195;p=thirdparty%2Flinux.git md/md-bitmap: fix GPF in bitmap_get_stats() The commit message of commit 6ec1f0239485 ("md/md-bitmap: fix stats collection for external bitmaps") states: Remove the external bitmap check as the statistics should be available regardless of bitmap storage location. Return -EINVAL only for invalid bitmap with no storage (neither in superblock nor in external file). But, the code does not adhere to the above, as it does only check for a valid super-block for "internal" bitmaps. Hence, we observe: Oops: GPF, probably for non-canonical address 0x1cd66f1f40000028 RIP: 0010:bitmap_get_stats+0x45/0xd0 Call Trace: seq_read_iter+0x2b9/0x46a seq_read+0x12f/0x180 proc_reg_read+0x57/0xb0 vfs_read+0xf6/0x380 ksys_read+0x6d/0xf0 do_syscall_64+0x8c/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e We fix this by checking the existence of a super-block for both the internal and external case. Fixes: 6ec1f0239485 ("md/md-bitmap: fix stats collection for external bitmaps") Cc: stable@vger.kernel.org Reported-by: Gerald Gibson Signed-off-by: Håkon Bugge Link: https://lore.kernel.org/linux-raid/20250702091035.2061312-1-haakon.bugge@oracle.com Signed-off-by: Yu Kuai --- diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index bd694910b01b0..7f524a26cebca 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -2366,8 +2366,7 @@ static int bitmap_get_stats(void *data, struct md_bitmap_stats *stats) if (!bitmap) return -ENOENT; - if (!bitmap->mddev->bitmap_info.external && - !bitmap->storage.sb_page) + if (!bitmap->storage.sb_page) return -EINVAL; sb = kmap_local_page(bitmap->storage.sb_page); stats->sync_size = le64_to_cpu(sb->sync_size);