CVE-2026-72420
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: md/raid5: avoid R5_Overlap races while breaking stripe batches KCSAN report a race in break_stripe_batch_list() vs. raid5_make_request() on sh->dev[i].flags (plain word write vs. atomic bit op).. and .. one possible scenario is: CPU1 CPU2 break_stripe_batch_list(sh1) -> handle sh2 -> lock(sh2) -> sh2->batch_head = NULL -> unlock(sh2) -> test_and_clear_bit(R5_Overlap, sh2->dev[i].flags) -> wake_up_bit(sh2->dev[i].flags) raid5_make_request() -> add_all_stripe_bios(sh2) -> lock(sh2) -> stripe_bio_overlaps(sh2) returns true batch_head is NULL, so new bio overlap exist bio on sh2 -> true -> set_bit(R5_Overlap, sh2->dev[i].flags) -> unlock(sh2) -> wait_on_bit(sh2->dev[i].flags) -> sh2->dev[i].flags = sh1->dev[i].flags & ~R5_Overlap No wait_up_bit(), CPU2 could be wait_on_bit() forever... Fix by : - Expand the protect zone. - Use batch_head's device flag's snaphot when no held head_sh->stripe_lock. - Move sh/head_sh->batch_head = NULL to the end of protected zone , and , any concurrent add_all_stripe_bios() grabs sh->stripe_lock now either: - see batch_head != null, and , is rejected by stripe_bio_overlaps() under the lock (no R5_Overlap wait ) , or , - sees batch_head == NULL, only after dev[i].flags has already been set and the prior R5_Overlap waiters worken. KCSAN report: ================================================ BUG: KCSAN: data-race in break_stripe_batch_list / raid5_make_request write (marked) to 0xffff8e89c8117548 of 8 bytes by task 4042 on cpu 0: raid5_make_request+0xea0/0x2930 md_handle_request+0x4a2/0xa40 md_submit_bio+0x109/0x1a0 __submit_bio+0x2ec/0x390 submit_bio_noacct_nocheck+0x457/0x710 submit_bio_noacct+0x2a7/0xc20 submit_bio+0x56/0x250 blkdev_direct_IO+0x54c/0xda0 blkdev_write_iter+0x38f/0x570 aio_write+0x22b/0x490 io_submit_one+0xa51/0xf70 __x64_sys_io_submit+0xf7/0x220 x64_sys_call+0x1907/0x1c60 do_syscall_64+0x130/0x570 entry_SYSCALL_64_after_hwframe+0x76/0x7e read to 0xffff8e89c8117548 of 8 bytes by task 4010 on cpu 5: break_stripe_batch_list+0x249/0x480 handle_stripe_clean_event+0x720/0x9b0 handle_stripe+0x32fb/0x4500 handle_active_stripes.isra.0+0x6e0/0xa50 raid5d+0x7e0/0xba0 md_thread+0x15a/0x2d0 kthread+0x1e3/0x220 ret_from_fork+0x37a/0x410 ret_from_fork_asm+0x1a/0x30 value changed: 0x0000000000000019 -> 0x0000000000000099 --> R5_Overlap
View original CVE JSON
{
"id": "CVE-2026-72420",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-08-15T06:22:15.743",
"lastModified": "2026-10-30T13:19:51.860",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd/raid5: avoid R5_Overlap races while breaking stripe batches\n\nKCSAN report a race in break_stripe_batch_list() vs. raid5_make_request()\non sh->dev[i].flags (plain word write vs. atomic bit op)..\n\nand .. one possible scenario is:\n\nCPU1 CPU2\nbreak_stripe_batch_list(sh1)\n-> handle sh2\n-> lock(sh2)\n-> sh2->batch_head = NULL\n-> unlock(sh2)\n-> test_and_clear_bit(R5_Overlap, sh2->dev[i].flags)\n-> wake_up_bit(sh2->dev[i].flags)\n raid5_make_request()\n -> add_all_stripe_bios(sh2)\n -> lock(sh2)\n -> stripe_bio_overlaps(sh2) returns true\n\t\t\t\t batch_head is NULL, so new bio overlap\n\t\t\t\t exist bio on sh2 -> true\n -> set_bit(R5_Overlap, sh2->dev[i].flags)\n -> unlock(sh2)\n -> wait_on_bit(sh2->dev[i].flags)\n-> sh2->dev[i].flags = sh1->dev[i].flags & ~R5_Overlap\n\nNo wait_up_bit(), CPU2 could be wait_on_bit() forever...\n\nFix by :\n- Expand the protect zone.\n- Use batch_head's device flag's snaphot when no held head_sh->stripe_lock.\n- Move sh/head_sh->batch_head = NULL to the end of protected zone , and ,\n any concurrent add_all_stripe_bios() grabs sh->stripe_lock now either:\n\t- see batch_head != null, and , is rejected by stripe_bio_overlaps()\n\t under the lock (no R5_Overlap wait ) , or ,\n\t- sees batch_head == NULL, only after dev[i].flags has already been\n\t set and the prior R5_Overlap waiters worken.\n\nKCSAN report:\n================================================\n BUG: KCSAN: data-race in break_stripe_batch_list / raid5_make_request\n\n write (marked) to 0xffff8e89c8117548 of 8 bytes by task 4042 on cpu 0:\n raid5_make_request+0xea0/0x2930\n md_handle_request+0x4a2/0xa40\n md_submit_bio+0x109/0x1a0\n __submit_bio+0x2ec/0x390\n submit_bio_noacct_nocheck+0x457/0x710\n submit_bio_noacct+0x2a7/0xc20\n submit_bio+0x56/0x250\n blkdev_direct_IO+0x54c/0xda0\n blkdev_write_iter+0x38f/0x570\n aio_write+0x22b/0x490\n io_submit_one+0xa51/0xf70\n __x64_sys_io_submit+0xf7/0x220\n x64_sys_call+0x1907/0x1c60\n do_syscall_64+0x130/0x570\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\n read to 0xffff8e89c8117548 of 8 bytes by task 4010 on cpu 5:\n break_stripe_batch_list+0x249/0x480\n handle_stripe_clean_event+0x720/0x9b0\n handle_stripe+0x32fb/0x4500\n handle_active_stripes.isra.0+0x6e0/0xa50\n raid5d+0x7e0/0xba0\n md_thread+0x15a/0x2d0\n kthread+0x1e3/0x220\n ret_from_fork+0x37a/0x410\n ret_from_fork_asm+0x1a/0x30\n\n value changed: 0x0000000000000019 -> 0x0000000000000099 --> R5_Overlap"
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"drivers/md/raid5.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "fb642b92c267beeefd352af9bc461eac93a7552c",
"lessThan": "205e33bad8ebf5674fbe6ec3ae3805878abb4f2c",
"versionType": "git",
"status": "affected"
},
{
"version": "fb642b92c267beeefd352af9bc461eac93a7552c",
"lessThan": "158a5480d51969adeb727ff20c6fa96f063e9f9e",
"versionType": "git",
"status": "affected"
},
{
"version": "fb642b92c267beeefd352af9bc461eac93a7552c",
"lessThan": "8031b0d02bd221a5f9add4357e291fc2a527b83a",
"versionType": "git",
"status": "affected"
},
{
"version": "fb642b92c267beeefd352af9bc461eac93a7552c",
"lessThan": "4d919c9b770996365806b6c8d701912d52baa306",
"versionType": "git",
"status": "affected"
},
{
"version": "fb642b92c267beeefd352af9bc461eac93a7552c",
"lessThan": "d684b72dfbd320623ccaab0779aa841190488e7c",
"versionType": "git",
"status": "affected"
},
{
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"lessThan": "55b77337bdd088c77461588e5ec094421b89911b",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"drivers/md/raid5.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "4.1",
"status": "affected"
},
{
"version": "0",
"lessThan": "4.1",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.191",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.160",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.97",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.40",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.1.5",
"lessThanOrEqual": "7.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 2.8,
"impactScore": 5.9
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-10-16T18:49:28.867554Z",
"id": "CVE-2026-72420",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"references": [
{
"url": "https://git.kernel.org/stable/c/158a5480d51969adeb727ff20c6fa96f063e9f9e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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{
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}