CVE-2024-26962: dm-raid456, md/raid456: fix a deadlock for dm-raid456 while io concurrent with reshape
First published: Wed May 01 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: dm-raid456, md/raid456: fix a deadlock for dm-raid456 while io concurrent with reshape For raid456, if reshape is still in progress, then IO across reshape position will wait for reshape to make progress. However, for dm-raid, in following cases reshape will never make progress hence IO will hang: 1) the array is read-only; 2) MD_RECOVERY_WAIT is set; 3) MD_RECOVERY_FROZEN is set; After commit c467e97f079f ("md/raid6: use valid sector values to determine if an I/O should wait on the reshape") fix the problem that IO across reshape position doesn't wait for reshape, the dm-raid test shell/lvconvert-raid-reshape.sh start to hang: [root@fedora ~]# cat /proc/979/stack [<0>] wait_woken+0x7d/0x90 [<0>] raid5_make_request+0x929/0x1d70 [raid456] [<0>] md_handle_request+0xc2/0x3b0 [md_mod] [<0>] raid_map+0x2c/0x50 [dm_raid] [<0>] __map_bio+0x251/0x380 [dm_mod] [<0>] dm_submit_bio+0x1f0/0x760 [dm_mod] [<0>] __submit_bio+0xc2/0x1c0 [<0>] submit_bio_noacct_nocheck+0x17f/0x450 [<0>] submit_bio_noacct+0x2bc/0x780 [<0>] submit_bio+0x70/0xc0 [<0>] mpage_readahead+0x169/0x1f0 [<0>] blkdev_readahead+0x18/0x30 [<0>] read_pages+0x7c/0x3b0 [<0>] page_cache_ra_unbounded+0x1ab/0x280 [<0>] force_page_cache_ra+0x9e/0x130 [<0>] page_cache_sync_ra+0x3b/0x110 [<0>] filemap_get_pages+0x143/0xa30 [<0>] filemap_read+0xdc/0x4b0 [<0>] blkdev_read_iter+0x75/0x200 [<0>] vfs_read+0x272/0x460 [<0>] ksys_read+0x7a/0x170 [<0>] __x64_sys_read+0x1c/0x30 [<0>] do_syscall_64+0xc6/0x230 [<0>] entry_SYSCALL_64_after_hwframe+0x6c/0x74 This is because reshape can't make progress. For md/raid, the problem doesn't exist because register new sync_thread doesn't rely on the IO to be done any more: 1) If array is read-only, it can switch to read-write by ioctl/sysfs; 2) md/raid never set MD_RECOVERY_WAIT; 3) If MD_RECOVERY_FROZEN is set, mddev_suspend() doesn't hold 'reconfig_mutex', hence it can be cleared and reshape can continue by sysfs api 'sync_action'. However, I'm not sure yet how to avoid the problem in dm-raid yet. This patch on the one hand make sure raid_message() can't change sync_thread() through raid_message() after presuspend(), on the other hand detect the above 3 cases before wait for IO do be done in dm_suspend(), and let dm-raid requeue those IO.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/kernel | <6.7.12 | 6.7.12 |
| redhat/kernel | <6.8.3 | 6.8.3 |
| redhat/kernel | <6.9 | 6.9 |
| Linux Linux kernel | <6.7.12 | |
| Linux Linux kernel | >=6.8<6.8.3 | |
| debian/linux | <=5.10.223-1<=5.10.226-1<=6.1.115-1<=6.1.119-1 | 6.12.5-1 6.12.6-1 |
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Reference Links
- https://git.kernel.org/stable/c/41425f96d7aa59bc865f60f5dda3d7697b555677
- https://git.kernel.org/stable/c/5943a34bf6bab5801e08a55f63e1b8d5bc90dae1
- https://git.kernel.org/stable/c/a8d249d770cb357d16a2097b548d2e4c1c137304
- https://launchpad.net/bugs/cve/CVE-2024-26962
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-26962
- https://nvd.nist.gov/vuln/detail/CVE-2024-26962
- https://security-tracker.debian.org/tracker/CVE-2024-26962
- https://ubuntu.com/security/CVE-2024-26962
- https://git.kernel.org/linus/41425f96d7aa59bc865f60f5dda3d7697b555677
- https://access.redhat.com/security/cve/CVE-2024-26962
- https://lore.kernel.org/linux-cve-announce/2024050130-CVE-2024-26962-cbb0@gregkh/T
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2278175
- https://access.redhat.com/errata/RHSA-2024:9315
- https://bugzilla.redhat.com/show_bug.cgi?id=2278174
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