In the Linux kernel, the following vulnerability has been resolved:
md: fix deadlock between mddev_suspend and flush bio
Deadlock occurs when mddev is being suspended while some flush bio is in progress. It is a complex issue.
T1. the first flush is at the ending stage, it clears 'mddev->flush_bio' and tries to submit data, but is blocked because mddev is suspended by T4. T2. the second flush sets 'mddev->flush_bio', and attempts to queue md_submit_flush_data(), which is already running (T1) and won't execute again if on the same CPU as T1. T3. the third flush inc active_io and tries to flush, but is blocked because 'mddev->flush_bio' is not NULL (set by T2). T4. mddev_suspend() is called and waits for active_io dec to 0 which is inc by T3.
T1 T2 T3 T4 (flush 1) (flush 2) (third 3) (suspend) md_submit_flush_data mddev->flush_bio = NULL; . . md_flush_request . mddev->flush_bio = bio . queue submit_flushes . . . . md_handle_request . . active_io + 1 . . md_flush_request . . wait !mddev->flush_bio . . . . mddev_suspend . . wait !active_io . . . submit_flushes . queue_work md_submit_flush_data . //md_submit_flush_data is already running (T1) . md_handle_request wait resume
The root issue is non-atomic inc/dec of active_io during flush process. active_io is dec before md_submit_flush_data is queued, and inc soon after md_submit_flush_data() run. md_flush_request active_io + 1 submit_flushes active_io - 1 md_submit_flush_data md_handle_request active_io + 1 make_request active_io - 1
If active_io is dec after md_handle_request() instead of within submit_flushes(), make_request() can be called directly intead of md_handle_request() in md_submit_flush_data(), and active_io will only inc and dec once in the whole flush process. Deadlock will be fixed.
Additionally, the only difference between fixing the issue and before is that there is no return error handling of make_request(). But after previous patch cleaned md_write_start(), make_requst() only return error in raid5_make_request() by dm-raid, see commit 41425f96d7aa ("dm-raid456, md/raid456: fix a deadlock for dm-raid456 while io concurrent with reshape)". Since dm always splits data and flush operation into two separate io, io size of flush submitted by dm always is 0, make_request() will not be called in md_submit_flush_data(). To prevent future modifications from introducing issues, add WARN_ON to ensure make_request() no error is returned in this context.
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon_linux_2023 | — | Upgrade kernel-toolsUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-tools-develUpgrade kernel-modules-extraUpgrade kernel-tools-debuginfoUpgrade kernel-develUpgrade python3-perfUpgrade kernel-libbpf-staticUpgrade bpftool-debuginfoUpgrade perfUpgrade kernel-debuginfoUpgrade bpftoolUpgrade python3-perf-debuginfoUpgrade kernel-libbpfUpgrade perf-debuginfoUpgrade kernel-headersUpgrade kernel-modules-extra-commonUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-libbpf-develUpgrade kernelUpgrade kernel-livepatch-6.1.106-116.188 | Oct 16, 2025 | Aug 17, 2024 |
| Debian | — | Upgrade linuxUpgrade linux-6.1 | Sep 2, 2024 | Aug 17, 2024 |
| Huawei Euleros 2_0_sp11 | — | Upgrade kernel-toolsUpgrade kernel-abi-stablelistsUpgrade kernelUpgrade kernel-tools-libsUpgrade python3-perfUpgrade bpftool | Dec 12, 2024 | Aug 17, 2024 |
| Huawei Euleros 2_0_sp12 | — | Upgrade python3-perfUpgrade bpftoolUpgrade kernelUpgrade kernel-abi-stablelistsUpgrade kernel-tools-libsUpgrade kernel-tools | Dec 12, 2024 | Aug 17, 2024 |
| Oracle_linux | — | Upgrade kernel | Apr 4, 2025 | Aug 17, 2024 |
| Redhat_linux | — | Upgrade kernel-rtNo solution existsUpgrade kernel | Apr 3, 2025 | Aug 17, 2024 |
| Suse | — | Upgrade kernel-rt-extraUpgrade kernel-develUpgrade kernel-64kb-optionalUpgrade cluster-md-kmp-rtUpgrade kernel-default-livepatch-develUpgrade ocfs2-kmp-azureUpgrade dtb-sprdUpgrade dtb-broadcomUpgrade kernel-debugUpgrade kselftests-kmp-azureUpgrade kernel-default-optionalUpgrade dtb-renesasUpgrade kernel-defaultUpgrade reiserfs-kmp-64kbUpgrade cluster-md-kmp-64kbUpgrade kernel-devel-rtUpgrade kernel-obs-buildUpgrade kernel-azure-extraUpgrade kernel-debug-vdsoUpgrade dtb-amdUpgrade ocfs2-kmp-defaultUpgrade kernel-64kb-extraUpgrade dtb-armUpgrade gfs2-kmp-azureUpgrade reiserfs-kmp-rtUpgrade dtb-xilinxUpgrade kernel-default-baseUpgrade kernel-debug-develUpgrade dlm-kmp-azureUpgrade dtb-allwinnerUpgrade dtb-appleUpgrade dlm-kmp-defaultUpgrade dtb-marvellUpgrade kselftests-kmp-rtUpgrade reiserfs-kmp-defaultUpgrade kernel-64kb-develUpgrade dtb-hisiliconUpgrade kernel-azureUpgrade dtb-caviumUpgrade kernel-kvmsmall-livepatch-develUpgrade dtb-socionextUpgrade dtb-nvidiaUpgrade kernel-source-vanillaUpgrade kernel-rt_debugUpgrade kernel-docs-htmlUpgrade kselftests-kmp-defaultUpgrade dlm-kmp-rtUpgrade kernel-rt_debug-livepatch-develUpgrade kernel-docsUpgrade gfs2-kmp-defaultUpgrade dtb-exynosUpgrade kernel-zfcpdumpUpgrade kernel-kvmsmall-develUpgrade kernel-rt-livepatch-develUpgrade kernel-rt-vdsoUpgrade kernel-azure-develUpgrade gfs2-kmp-64kbUpgrade kernel-obs-qaUpgrade kernel-rt-develUpgrade dtb-rockchipUpgrade kernel-default-livepatchUpgrade kernel-default-extraUpgrade kernel-rt_debug-vdsoUpgrade cluster-md-kmp-azureUpgrade kernel-64kbUpgrade dtb-qcomUpgrade dtb-freescaleUpgrade kernel-64kb-livepatch-develUpgrade ocfs2-kmp-64kbUpgrade kernel-syms-azureUpgrade kernel-azure-livepatch-develUpgrade dtb-lgUpgrade dtb-alteraUpgrade kernel-azure-vdsoUpgrade kernel-macrosUpgrade kernel-kvmsmall-vdsoUpgrade kernel-azure-optionalUpgrade kernel-rtUpgrade kernel-kvmsmallUpgrade kernel-debug-livepatch-develUpgrade dtb-amazonUpgrade cluster-md-kmp-defaultUpgrade ocfs2-kmp-rtUpgrade kernel-default-vdsoUpgrade dlm-kmp-64kbUpgrade kernel-default-develUpgrade kernel-symsUpgrade kernel-rt_debug-develUpgrade kselftests-kmp-64kbUpgrade kernel-source-rtUpgrade kernel-rt-optionalUpgrade kernel-syms-rtUpgrade dtb-mediatekUpgrade dtb-amlogicUpgrade dtb-apmUpgrade reiserfs-kmp-azureUpgrade kernel-devel-azureUpgrade kernel-default-base-rebuildUpgrade kernel-source-azureUpgrade kernel-sourceUpgrade gfs2-kmp-rt | Dec 5, 2025 | Apr 4, 2025 |
| Ubuntu | — | Upgrade linux-image-6.8.0-1015-oracle-64kUpgrade linux-image-azureUpgrade linux-image-kvmUpgrade linux-image-nvidia-6.8Upgrade linux-image-nvidia-64kUpgrade linux-image-6.8.0-1015-oracleUpgrade linux-image-6.8.0-1017-gcpUpgrade linux-image-awsUpgrade linux-image-nvidia-hwe-22.04Upgrade linux-image-6.8.0-1018-awsUpgrade linux-image-virtual-hwe-22.04Upgrade linux-image-oracle-64kUpgrade linux-image-oem-24.04Upgrade linux-image-oem-22.04dUpgrade linux-image-raspiUpgrade linux-image-gkeUpgrade linux-image-nvidia-lowlatencyUpgrade linux-image-6.8.0-1016-oemUpgrade linux-image-6.8.0-1017-azureUpgrade linux-image-6.8.0-1016-azureUpgrade linux-image-6.8.0-1017-azure-fdeUpgrade linux-image-oem-24.04aUpgrade linux-image-generic-hwe-24.04Upgrade linux-image-oem-22.04cUpgrade linux-image-6.8.0-1013-gkeUpgrade linux-image-6.8.0-1014-ibmUpgrade linux-image-lowlatency-64k-hwe-22.04Upgrade linux-image-6.8.0-48-genericUpgrade linux-image-6.8.0-1017-nvidiaUpgrade linux-image-6.8.0-48-lowlatency-64kUpgrade linux-image-generic-64k-hwe-22.04Upgrade linux-image-generic-hwe-22.04Upgrade linux-image-6.8.0-1016-azure-fdeUpgrade linux-image-6.8.0-1017-nvidia-lowlatencyUpgrade linux-image-nvidia-lowlatency-64kUpgrade linux-image-ibm-classicUpgrade linux-image-oracleUpgrade linux-image-gcpUpgrade linux-image-generic-64kUpgrade linux-image-6.8.0-48-generic-64kUpgrade linux-image-ibm-lts-24.04Upgrade linux-image-azure-fdeUpgrade linux-image-lowlatency-64kUpgrade linux-image-generic-64k-hwe-24.04Upgrade linux-image-virtualUpgrade linux-image-6.8.0-1014-raspiUpgrade linux-image-genericUpgrade linux-image-6.8.0-48-lowlatencyUpgrade linux-image-nvidia-64k-6.8Upgrade linux-image-lowlatency-hwe-24.04Upgrade linux-image-gkeopUpgrade linux-image-oem-22.04bUpgrade linux-image-6.8.0-1002-gkeopUpgrade linux-image-oem-22.04aUpgrade linux-image-lowlatency-hwe-22.04Upgrade linux-image-6.8.0-1017-nvidia-64kUpgrade linux-image-lowlatencyUpgrade linux-image-6.8.0-1016-gcpUpgrade linux-image-oem-22.04Upgrade linux-image-virtual-hwe-24.04Upgrade linux-image-nvidiaUpgrade linux-image-nvidia-64k-hwe-22.04Upgrade linux-image-generic-lpaeUpgrade linux-image-ibmUpgrade linux-image-6.8.0-1017-nvidia-lowlatency-64kUpgrade linux-image-lowlatency-64k-hwe-24.04Upgrade linux-image-gkeop-6.8 | Nov 4, 2024 | Aug 17, 2024 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Jan 20, 2025 | Aug 17, 2024 |
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