CVE-2025-38358 (GCVE-0-2025-38358)
Vulnerability from cvelistv5
Published
2025-07-25 12:47
Modified
2025-07-28 04:19
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix race between async reclaim worker and close_ctree()
Syzbot reported an assertion failure due to an attempt to add a delayed
iput after we have set BTRFS_FS_STATE_NO_DELAYED_IPUT in the fs_info
state:
WARNING: CPU: 0 PID: 65 at fs/btrfs/inode.c:3420 btrfs_add_delayed_iput+0x2f8/0x370 fs/btrfs/inode.c:3420
Modules linked in:
CPU: 0 UID: 0 PID: 65 Comm: kworker/u8:4 Not tainted 6.15.0-next-20250530-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: btrfs-endio-write btrfs_work_helper
RIP: 0010:btrfs_add_delayed_iput+0x2f8/0x370 fs/btrfs/inode.c:3420
Code: 4e ad 5d (...)
RSP: 0018:ffffc9000213f780 EFLAGS: 00010293
RAX: ffffffff83c635b7 RBX: ffff888058920000 RCX: ffff88801c769e00
RDX: 0000000000000000 RSI: 0000000000000100 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffff888058921b67 R09: 1ffff1100b12436c
R10: dffffc0000000000 R11: ffffed100b12436d R12: 0000000000000001
R13: dffffc0000000000 R14: ffff88807d748000 R15: 0000000000000100
FS: 0000000000000000(0000) GS:ffff888125c53000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000bd038 CR3: 000000006a142000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
btrfs_put_ordered_extent+0x19f/0x470 fs/btrfs/ordered-data.c:635
btrfs_finish_one_ordered+0x11d8/0x1b10 fs/btrfs/inode.c:3312
btrfs_work_helper+0x399/0xc20 fs/btrfs/async-thread.c:312
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
This can happen due to a race with the async reclaim worker like this:
1) The async metadata reclaim worker enters shrink_delalloc(), which calls
btrfs_start_delalloc_roots() with an nr_pages argument that has a value
less than LONG_MAX, and that in turn enters start_delalloc_inodes(),
which sets the local variable 'full_flush' to false because
wbc->nr_to_write is less than LONG_MAX;
2) There it finds inode X in a root's delalloc list, grabs a reference for
inode X (with igrab()), and triggers writeback for it with
filemap_fdatawrite_wbc(), which creates an ordered extent for inode X;
3) The unmount sequence starts from another task, we enter close_ctree()
and we flush the workqueue fs_info->endio_write_workers, which waits
for the ordered extent for inode X to complete and when dropping the
last reference of the ordered extent, with btrfs_put_ordered_extent(),
when we call btrfs_add_delayed_iput() we don't add the inode to the
list of delayed iputs because it has a refcount of 2, so we decrement
it to 1 and return;
4) Shortly after at close_ctree() we call btrfs_run_delayed_iputs() which
runs all delayed iputs, and then we set BTRFS_FS_STATE_NO_DELAYED_IPUT
in the fs_info state;
5) The async reclaim worker, after calling filemap_fdatawrite_wbc(), now
calls btrfs_add_delayed_iput() for inode X and there we trigger an
assertion failure since the fs_info state has the flag
BTRFS_FS_STATE_NO_DELAYED_IPUT set.
Fix this by setting BTRFS_FS_STATE_NO_DELAYED_IPUT only after we wait for
the async reclaim workers to finish, after we call cancel_work_sync() for
them at close_ctree(), and by running delayed iputs after wait for the
reclaim workers to finish and before setting the bit.
This race was recently introduced by commit 19e60b2a95f5 ("btrfs: add
extra warning if delayed iput is added when it's not allowed"). Without
the new validation at btrfs_add_delayed_iput(),
---truncated---
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/btrfs/disk-io.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "4693cda2c06039c875f2eef0123b22340c34bfa0",
"status": "affected",
"version": "19e60b2a95f5d6b77d972c7bec35a11e70fd118c",
"versionType": "git"
},
{
"lessThan": "a26bf338cdad3643a6e7c3d78a172baadba15c1a",
"status": "affected",
"version": "19e60b2a95f5d6b77d972c7bec35a11e70fd118c",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/btrfs/disk-io.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.15"
},
{
"lessThan": "6.15",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.15.*",
"status": "unaffected",
"version": "6.15.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.16",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.15.5",
"versionStartIncluding": "6.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.16",
"versionStartIncluding": "6.15",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
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}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix race between async reclaim worker and close_ctree()\n\nSyzbot reported an assertion failure due to an attempt to add a delayed\niput after we have set BTRFS_FS_STATE_NO_DELAYED_IPUT in the fs_info\nstate:\n\n WARNING: CPU: 0 PID: 65 at fs/btrfs/inode.c:3420 btrfs_add_delayed_iput+0x2f8/0x370 fs/btrfs/inode.c:3420\n Modules linked in:\n CPU: 0 UID: 0 PID: 65 Comm: kworker/u8:4 Not tainted 6.15.0-next-20250530-syzkaller #0 PREEMPT(full)\n Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025\n Workqueue: btrfs-endio-write btrfs_work_helper\n RIP: 0010:btrfs_add_delayed_iput+0x2f8/0x370 fs/btrfs/inode.c:3420\n Code: 4e ad 5d (...)\n RSP: 0018:ffffc9000213f780 EFLAGS: 00010293\n RAX: ffffffff83c635b7 RBX: ffff888058920000 RCX: ffff88801c769e00\n RDX: 0000000000000000 RSI: 0000000000000100 RDI: 0000000000000000\n RBP: 0000000000000001 R08: ffff888058921b67 R09: 1ffff1100b12436c\n R10: dffffc0000000000 R11: ffffed100b12436d R12: 0000000000000001\n R13: dffffc0000000000 R14: ffff88807d748000 R15: 0000000000000100\n FS: 0000000000000000(0000) GS:ffff888125c53000(0000) knlGS:0000000000000000\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00002000000bd038 CR3: 000000006a142000 CR4: 00000000003526f0\n DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n Call Trace:\n \u003cTASK\u003e\n btrfs_put_ordered_extent+0x19f/0x470 fs/btrfs/ordered-data.c:635\n btrfs_finish_one_ordered+0x11d8/0x1b10 fs/btrfs/inode.c:3312\n btrfs_work_helper+0x399/0xc20 fs/btrfs/async-thread.c:312\n process_one_work kernel/workqueue.c:3238 [inline]\n process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321\n worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402\n kthread+0x70e/0x8a0 kernel/kthread.c:464\n ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n \u003c/TASK\u003e\n\nThis can happen due to a race with the async reclaim worker like this:\n\n1) The async metadata reclaim worker enters shrink_delalloc(), which calls\n btrfs_start_delalloc_roots() with an nr_pages argument that has a value\n less than LONG_MAX, and that in turn enters start_delalloc_inodes(),\n which sets the local variable \u0027full_flush\u0027 to false because\n wbc-\u003enr_to_write is less than LONG_MAX;\n\n2) There it finds inode X in a root\u0027s delalloc list, grabs a reference for\n inode X (with igrab()), and triggers writeback for it with\n filemap_fdatawrite_wbc(), which creates an ordered extent for inode X;\n\n3) The unmount sequence starts from another task, we enter close_ctree()\n and we flush the workqueue fs_info-\u003eendio_write_workers, which waits\n for the ordered extent for inode X to complete and when dropping the\n last reference of the ordered extent, with btrfs_put_ordered_extent(),\n when we call btrfs_add_delayed_iput() we don\u0027t add the inode to the\n list of delayed iputs because it has a refcount of 2, so we decrement\n it to 1 and return;\n\n4) Shortly after at close_ctree() we call btrfs_run_delayed_iputs() which\n runs all delayed iputs, and then we set BTRFS_FS_STATE_NO_DELAYED_IPUT\n in the fs_info state;\n\n5) The async reclaim worker, after calling filemap_fdatawrite_wbc(), now\n calls btrfs_add_delayed_iput() for inode X and there we trigger an\n assertion failure since the fs_info state has the flag\n BTRFS_FS_STATE_NO_DELAYED_IPUT set.\n\nFix this by setting BTRFS_FS_STATE_NO_DELAYED_IPUT only after we wait for\nthe async reclaim workers to finish, after we call cancel_work_sync() for\nthem at close_ctree(), and by running delayed iputs after wait for the\nreclaim workers to finish and before setting the bit.\n\nThis race was recently introduced by commit 19e60b2a95f5 (\"btrfs: add\nextra warning if delayed iput is added when it\u0027s not allowed\"). Without\nthe new validation at btrfs_add_delayed_iput(), \n---truncated---"
}
],
"providerMetadata": {
"dateUpdated": "2025-07-28T04:19:50.121Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/4693cda2c06039c875f2eef0123b22340c34bfa0"
},
{
"url": "https://git.kernel.org/stable/c/a26bf338cdad3643a6e7c3d78a172baadba15c1a"
}
],
"title": "btrfs: fix race between async reclaim worker and close_ctree()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2025-38358",
"datePublished": "2025-07-25T12:47:29.515Z",
"dateReserved": "2025-04-16T04:51:24.007Z",
"dateUpdated": "2025-07-28T04:19:50.121Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2025-38358\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-07-25T13:15:24.573\",\"lastModified\":\"2025-07-25T15:29:19.837\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbtrfs: fix race between async reclaim worker and close_ctree()\\n\\nSyzbot reported an assertion failure due to an attempt to add a delayed\\niput after we have set BTRFS_FS_STATE_NO_DELAYED_IPUT in the fs_info\\nstate:\\n\\n WARNING: CPU: 0 PID: 65 at fs/btrfs/inode.c:3420 btrfs_add_delayed_iput+0x2f8/0x370 fs/btrfs/inode.c:3420\\n Modules linked in:\\n CPU: 0 UID: 0 PID: 65 Comm: kworker/u8:4 Not tainted 6.15.0-next-20250530-syzkaller #0 PREEMPT(full)\\n Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025\\n Workqueue: btrfs-endio-write btrfs_work_helper\\n RIP: 0010:btrfs_add_delayed_iput+0x2f8/0x370 fs/btrfs/inode.c:3420\\n Code: 4e ad 5d (...)\\n RSP: 0018:ffffc9000213f780 EFLAGS: 00010293\\n RAX: ffffffff83c635b7 RBX: ffff888058920000 RCX: ffff88801c769e00\\n RDX: 0000000000000000 RSI: 0000000000000100 RDI: 0000000000000000\\n RBP: 0000000000000001 R08: ffff888058921b67 R09: 1ffff1100b12436c\\n R10: dffffc0000000000 R11: ffffed100b12436d R12: 0000000000000001\\n R13: dffffc0000000000 R14: ffff88807d748000 R15: 0000000000000100\\n FS: 0000000000000000(0000) GS:ffff888125c53000(0000) knlGS:0000000000000000\\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\\n CR2: 00002000000bd038 CR3: 000000006a142000 CR4: 00000000003526f0\\n DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\\n DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\\n Call Trace:\\n \u003cTASK\u003e\\n btrfs_put_ordered_extent+0x19f/0x470 fs/btrfs/ordered-data.c:635\\n btrfs_finish_one_ordered+0x11d8/0x1b10 fs/btrfs/inode.c:3312\\n btrfs_work_helper+0x399/0xc20 fs/btrfs/async-thread.c:312\\n process_one_work kernel/workqueue.c:3238 [inline]\\n process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321\\n worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402\\n kthread+0x70e/0x8a0 kernel/kthread.c:464\\n ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148\\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\\n \u003c/TASK\u003e\\n\\nThis can happen due to a race with the async reclaim worker like this:\\n\\n1) The async metadata reclaim worker enters shrink_delalloc(), which calls\\n btrfs_start_delalloc_roots() with an nr_pages argument that has a value\\n less than LONG_MAX, and that in turn enters start_delalloc_inodes(),\\n which sets the local variable \u0027full_flush\u0027 to false because\\n wbc-\u003enr_to_write is less than LONG_MAX;\\n\\n2) There it finds inode X in a root\u0027s delalloc list, grabs a reference for\\n inode X (with igrab()), and triggers writeback for it with\\n filemap_fdatawrite_wbc(), which creates an ordered extent for inode X;\\n\\n3) The unmount sequence starts from another task, we enter close_ctree()\\n and we flush the workqueue fs_info-\u003eendio_write_workers, which waits\\n for the ordered extent for inode X to complete and when dropping the\\n last reference of the ordered extent, with btrfs_put_ordered_extent(),\\n when we call btrfs_add_delayed_iput() we don\u0027t add the inode to the\\n list of delayed iputs because it has a refcount of 2, so we decrement\\n it to 1 and return;\\n\\n4) Shortly after at close_ctree() we call btrfs_run_delayed_iputs() which\\n runs all delayed iputs, and then we set BTRFS_FS_STATE_NO_DELAYED_IPUT\\n in the fs_info state;\\n\\n5) The async reclaim worker, after calling filemap_fdatawrite_wbc(), now\\n calls btrfs_add_delayed_iput() for inode X and there we trigger an\\n assertion failure since the fs_info state has the flag\\n BTRFS_FS_STATE_NO_DELAYED_IPUT set.\\n\\nFix this by setting BTRFS_FS_STATE_NO_DELAYED_IPUT only after we wait for\\nthe async reclaim workers to finish, after we call cancel_work_sync() for\\nthem at close_ctree(), and by running delayed iputs after wait for the\\nreclaim workers to finish and before setting the bit.\\n\\nThis race was recently introduced by commit 19e60b2a95f5 (\\\"btrfs: add\\nextra warning if delayed iput is added when it\u0027s not allowed\\\"). Without\\nthe new validation at btrfs_add_delayed_iput(), \\n---truncated---\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/4693cda2c06039c875f2eef0123b22340c34bfa0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a26bf338cdad3643a6e7c3d78a172baadba15c1a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
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- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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