kernel/linux.git/drivers/md/md-bitmap.c, branch v6.6.132

md/bitmap: fix GPF in write_page caused by resize race

2026-03-04T12:21:12+00:00

[ Upstream commit 46ef85f854dfa9d5226b3c1c46493d79556c9589 ] A General Protection Fault occurs in write_page() during array resize: RIP: 0010:write_page+0x22b/0x3c0 [md_mod] This is a use-after-free race between bitmap_daemon_work() and __bitmap_resize(). The daemon iterates over `bitmap->storage.filemap` without locking, while the resize path frees that storage via md_bitmap_file_unmap(). `quiesce()` does not stop the md thread, allowing concurrent access to freed pages. Fix by holding `mddev->bitmap_info.mutex` during the bitmap update. Link: https://lore.kernel.org/linux-raid/20260120102456.25169-1-jinpu.wang@ionos.com Closes: https://lore.kernel.org/linux-raid/CAMGffE=Mbfp=7xD_hYxXk1PAaCZNSEAVeQGKGy7YF9f2S4=NEA@mail.gmail.com/T/#u Cc: stable@vger.kernel.org Fixes: d60b479d177a ("md/bitmap: add bitmap_resize function to allow bitmap resizing.") Signed-off-by: Jack Wang Signed-off-by: Yu Kuai Signed-off-by: Sasha Levin

md/md-bitmap: fix GPF in bitmap_get_stats()

2025-07-17T16:35:13+00:00

commit c17fb542dbd1db745c9feac15617056506dd7195 upstream. 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 Signed-off-by: Greg Kroah-Hartman

md/md-bitmap: fix dm-raid max_write_behind setting

2025-07-06T09:00:07+00:00

[ Upstream commit 2afe17794cfed5f80295b1b9facd66e6f65e5002 ] It's supposed to be COUNTER_MAX / 2, not COUNTER_MAX. Link: https://lore.kernel.org/linux-raid/20250524061320.370630-14-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Signed-off-by: Sasha Levin

md/md-bitmap: fix stats collection for external bitmaps

2025-04-25T08:45:39+00:00

[ Upstream commit 6ec1f0239485028445d213d91cfee5242f3211ba ] The bitmap_get_stats() function incorrectly returns -ENOENT for external bitmaps. 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). Note: "bitmap_info.external" here refers to a bitmap stored in a separate file (bitmap_file), not to external metadata. Fixes: 8d28d0ddb986 ("md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime") Signed-off-by: Zheng Qixing Link: https://lore.kernel.org/linux-raid/20250403015322.2873369-1-zhengqixing@huaweicloud.com Signed-off-by: Yu Kuai Signed-off-by: Sasha Levin

md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime

2025-02-27T12:10:44+00:00

[ Upstream commit 8d28d0ddb986f56920ac97ae704cc3340a699a30 ] After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct md_bitmap_stats"), following panic is reported: Oops: general protection fault, probably for non-canonical address RIP: 0010:bitmap_get_stats+0x2b/0xa0 Call Trace: md_seq_show+0x2d2/0x5b0 seq_read_iter+0x2b9/0x470 seq_read+0x12f/0x180 proc_reg_read+0x57/0xb0 vfs_read+0xf6/0x380 ksys_read+0x6c/0xf0 do_syscall_64+0x82/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e Root cause is that bitmap_get_stats() can be called at anytime if mddev is still there, even if bitmap is destroyed, or not fully initialized. Deferenceing bitmap in this case can crash the kernel. Meanwhile, the above commit start to deferencing bitmap->storage, make the problem easier to trigger. Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex. Cc: stable@vger.kernel.org # v6.12+ Fixes: 32a7627cf3a3 ("[PATCH] md: optimised resync using Bitmap based intent logging") Reported-and-tested-by: Harshit Mogalapalli Closes: https://lore.kernel.org/linux-raid/ca3a91a2-50ae-4f68-b317-abd9889f3907@oracle.com/T/#m6e5086c95201135e4941fe38f9efa76daf9666c5 Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20250124092055.4050195-1-yukuai1@huaweicloud.com Signed-off-by: Song Liu Signed-off-by: Sasha Levin

md/md-bitmap: add 'sync_size' into struct md_bitmap_stats

2025-02-27T12:10:44+00:00

[ Upstream commit ec6bb299c7c3dd4ca1724d13d5f5fae3ee54fc65 ] To avoid dereferencing bitmap directly in md-cluster to prepare inventing a new bitmap. BTW, also fix following checkpatch warnings: WARNING: Deprecated use of 'kmap_atomic', prefer 'kmap_local_page' instead WARNING: Deprecated use of 'kunmap_atomic', prefer 'kunmap_local' instead Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20240826074452.1490072-7-yukuai1@huaweicloud.com Signed-off-by: Song Liu Stable-dep-of: 8d28d0ddb986 ("md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime") Signed-off-by: Sasha Levin

md/md-bitmap: replace md_bitmap_status() with a new helper md_bitmap_get_stats()

2025-02-27T12:10:44+00:00

[ Upstream commit 38f287d7e495ae00d4481702f44ff7ca79f5c9bc ] There are no functional changes, and the new helper will be used in multiple places in following patches to avoid dereferencing bitmap directly. Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20240826074452.1490072-3-yukuai1@huaweicloud.com Signed-off-by: Song Liu Stable-dep-of: 8d28d0ddb986 ("md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime") Signed-off-by: Sasha Levin

md/md-bitmap: move bitmap_{start, end}write to md upper layer

2025-02-21T12:57:26+00:00

commit cd5fc653381811f1e0ba65f5d169918cab61476f upstream. There are two BUG reports that raid5 will hang at bitmap_startwrite([1],[2]), root cause is that bitmap start write and end write is unbalanced, it's not quite clear where, and while reviewing raid5 code, it's found that bitmap operations can be optimized. For example, for a 4 disks raid5, with chunksize=8k, if user issue a IO (0 + 48k) to the array: ┌────────────────────────────────────────────────────────────┐ │chunk 0 │ │ ┌────────────┬─────────────┬─────────────┬────────────┼ │ sh0 │A0: 0 + 4k │A1: 8k + 4k │A2: 16k + 4k │A3: P │ │ ┼────────────┼─────────────┼─────────────┼────────────┼ │ sh1 │B0: 4k + 4k │B1: 12k + 4k │B2: 20k + 4k │B3: P │ ┼──────┴────────────┴─────────────┴─────────────┴────────────┼ │chunk 1 │ │ ┌────────────┬─────────────┬─────────────┬────────────┤ │ sh2 │C0: 24k + 4k│C1: 32k + 4k │C2: P │C3: 40k + 4k│ │ ┼────────────┼─────────────┼─────────────┼────────────┼ │ sh3 │D0: 28k + 4k│D1: 36k + 4k │D2: P │D3: 44k + 4k│ └──────┴────────────┴─────────────┴─────────────┴────────────┘ Before this patch, 4 stripe head will be used, and each sh will attach bio for 3 disks, and each attached bio will trigger bitmap_startwrite() once, which means total 12 times. - 3 times (0 + 4k), for (A0, A1 and A2) - 3 times (4 + 4k), for (B0, B1 and B2) - 3 times (8 + 4k), for (C0, C1 and C3) - 3 times (12 + 4k), for (D0, D1 and D3) After this patch, md upper layer will calculate that IO range (0 + 48k) is corresponding to the bitmap (0 + 16k), and call bitmap_startwrite() just once. Noted that this patch will align bitmap ranges to the chunks, for example, if user issue a IO (0 + 4k) to array: - Before this patch, 1 time (0 + 4k), for A0; - After this patch, 1 time (0 + 8k) for chunk 0; Usually, one bitmap bit will represent more than one disk chunk, and this doesn't have any difference. And even if user really created a array that one chunk contain multiple bits, the overhead is that more data will be recovered after power failure. Also remove STRIPE_BITMAP_PENDING since it's not used anymore. [1] https://lore.kernel.org/all/CAJpMwyjmHQLvm6zg1cmQErttNNQPDAAXPKM3xgTjMhbfts986Q@mail.gmail.com/ [2] https://lore.kernel.org/all/ADF7D720-5764-4AF3-B68E-1845988737AA@flyingcircus.io/ Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20250109015145.158868-6-yukuai1@huaweicloud.com Signed-off-by: Song Liu [There is no bitmap_operations, resolve conflicts by replacing bitmap_ops->{startwrite, endwrite} with md_bitmap_{startwrite, endwrite}] Signed-off-by: Yu Kuai Signed-off-by: Greg Kroah-Hartman

md/md-bitmap: remove the last parameter for bimtap_ops->endwrite()

2025-02-21T12:57:26+00:00

commit 4f0e7d0e03b7b80af84759a9e7cfb0f81ac4adae upstream. For the case that IO failed for one rdev, the bit will be mark as NEEDED in following cases: 1) If badblocks is set and rdev is not faulty; 2) If rdev is faulty; Case 1) is useless because synchronize data to badblocks make no sense. Case 2) can be replaced with mddev->degraded. Also remove R1BIO_Degraded, R10BIO_Degraded and STRIPE_DEGRADED since case 2) no longer use them. Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20250109015145.158868-3-yukuai1@huaweicloud.com Signed-off-by: Song Liu [ Resolve minor conflicts ] Signed-off-by: Yu Kuai Signed-off-by: Greg Kroah-Hartman

md/md-bitmap: factor behind write counters out from bitmap_{start/end}write()

2025-02-21T12:57:25+00:00

commit 08c50142a128dcb2d7060aa3b4c5db8837f7a46a upstream. behind_write is only used in raid1, prepare to refactor bitmap_{start/end}write(), there are no functional changes. Signed-off-by: Yu Kuai Reviewed-by: Xiao Ni Link: https://lore.kernel.org/r/20250109015145.158868-2-yukuai1@huaweicloud.com Signed-off-by: Song Liu [There is no bitmap_operations, resolve conflicts by exporting new api md_bitmap_{start,end}_behind_write] Signed-off-by: Yu Kuai Signed-off-by: Greg Kroah-Hartman