ghsa-38p5-w7j2-vwrv
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
jbd2: prevent softlockup in jbd2_log_do_checkpoint()
Both jbd2_log_do_checkpoint() and jbd2_journal_shrink_checkpoint_list() periodically release j_list_lock after processing a batch of buffers to avoid long hold times on the j_list_lock. However, since both functions contend for j_list_lock, the combined time spent waiting and processing can be significant.
jbd2_journal_shrink_checkpoint_list() explicitly calls cond_resched() when need_resched() is true to avoid softlockups during prolonged operations. But jbd2_log_do_checkpoint() only exits its loop when need_resched() is true, relying on potentially sleeping functions like __flush_batch() or wait_on_buffer() to trigger rescheduling. If those functions do not sleep, the kernel may hit a softlockup.
watchdog: BUG: soft lockup - CPU#3 stuck for 156s! [kworker/u129:2:373] CPU: 3 PID: 373 Comm: kworker/u129:2 Kdump: loaded Not tainted 6.6.0+ #10 Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.27 06/13/2017 Workqueue: writeback wb_workfn (flush-7:2) pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : native_queued_spin_lock_slowpath+0x358/0x418 lr : jbd2_log_do_checkpoint+0x31c/0x438 [jbd2] Call trace: native_queued_spin_lock_slowpath+0x358/0x418 jbd2_log_do_checkpoint+0x31c/0x438 [jbd2] __jbd2_log_wait_for_space+0xfc/0x2f8 [jbd2] add_transaction_credits+0x3bc/0x418 [jbd2] start_this_handle+0xf8/0x560 [jbd2] jbd2__journal_start+0x118/0x228 [jbd2] __ext4_journal_start_sb+0x110/0x188 [ext4] ext4_do_writepages+0x3dc/0x740 [ext4] ext4_writepages+0xa4/0x190 [ext4] do_writepages+0x94/0x228 __writeback_single_inode+0x48/0x318 writeback_sb_inodes+0x204/0x590 __writeback_inodes_wb+0x54/0xf8 wb_writeback+0x2cc/0x3d8 wb_do_writeback+0x2e0/0x2f8 wb_workfn+0x80/0x2a8 process_one_work+0x178/0x3e8 worker_thread+0x234/0x3b8 kthread+0xf0/0x108 ret_from_fork+0x10/0x20
So explicitly call cond_resched() in jbd2_log_do_checkpoint() to avoid softlockup.
{
"affected": [],
"aliases": [
"CVE-2025-39782"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-11T17:15:44Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\njbd2: prevent softlockup in jbd2_log_do_checkpoint()\n\nBoth jbd2_log_do_checkpoint() and jbd2_journal_shrink_checkpoint_list()\nperiodically release j_list_lock after processing a batch of buffers to\navoid long hold times on the j_list_lock. However, since both functions\ncontend for j_list_lock, the combined time spent waiting and processing\ncan be significant.\n\njbd2_journal_shrink_checkpoint_list() explicitly calls cond_resched() when\nneed_resched() is true to avoid softlockups during prolonged operations.\nBut jbd2_log_do_checkpoint() only exits its loop when need_resched() is\ntrue, relying on potentially sleeping functions like __flush_batch() or\nwait_on_buffer() to trigger rescheduling. If those functions do not sleep,\nthe kernel may hit a softlockup.\n\nwatchdog: BUG: soft lockup - CPU#3 stuck for 156s! [kworker/u129:2:373]\nCPU: 3 PID: 373 Comm: kworker/u129:2 Kdump: loaded Not tainted 6.6.0+ #10\nHardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.27 06/13/2017\nWorkqueue: writeback wb_workfn (flush-7:2)\npstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)\npc : native_queued_spin_lock_slowpath+0x358/0x418\nlr : jbd2_log_do_checkpoint+0x31c/0x438 [jbd2]\nCall trace:\n native_queued_spin_lock_slowpath+0x358/0x418\n jbd2_log_do_checkpoint+0x31c/0x438 [jbd2]\n __jbd2_log_wait_for_space+0xfc/0x2f8 [jbd2]\n add_transaction_credits+0x3bc/0x418 [jbd2]\n start_this_handle+0xf8/0x560 [jbd2]\n jbd2__journal_start+0x118/0x228 [jbd2]\n __ext4_journal_start_sb+0x110/0x188 [ext4]\n ext4_do_writepages+0x3dc/0x740 [ext4]\n ext4_writepages+0xa4/0x190 [ext4]\n do_writepages+0x94/0x228\n __writeback_single_inode+0x48/0x318\n writeback_sb_inodes+0x204/0x590\n __writeback_inodes_wb+0x54/0xf8\n wb_writeback+0x2cc/0x3d8\n wb_do_writeback+0x2e0/0x2f8\n wb_workfn+0x80/0x2a8\n process_one_work+0x178/0x3e8\n worker_thread+0x234/0x3b8\n kthread+0xf0/0x108\n ret_from_fork+0x10/0x20\n\nSo explicitly call cond_resched() in jbd2_log_do_checkpoint() to avoid\nsoftlockup.",
"id": "GHSA-38p5-w7j2-vwrv",
"modified": "2025-09-11T18:35:52Z",
"published": "2025-09-11T18:35:52Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39782"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/26cb9aad94cb1811d8fae115594cc71fa3d91ab0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3faac5e1d14c63260fd1bf789d96bde3ab3d9e54"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/41f40038de62e8306897cf6840791b268996432a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/429d50cbaff45090d52a1ea850d5de8c14881ee7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/84ff98c1ea19acd3f9389e4bb6061364e943f85e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9d98cf4632258720f18265a058e62fde120c0151"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f683d611518d30334813eecf9a8c687453e2800e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f7ee8fd689e6d534f9fd2494b9266f7998082e65"
}
],
"schema_version": "1.4.0",
"severity": []
}
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