CVE-2026-68367
usb: gadget: f_tcm: synchronize delayed set_alt with teardown
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_tcm: synchronize delayed set_alt with teardown The f_tcm set_alt() path defers endpoint setup to a work item and completes the delayed status response from process context. The delayed work uses f_tcm private state and may complete the setup request after disconnect or function teardown has already moved on. Cancel and drain the delayed set_alt work when the function is unbound or freed. For disable paths, which are reached under the composite device lock, use a small state machine and a non-sleeping cancellation path instead of cancel_work_sync(). If the work is already running, mark it cancelled and let the worker own the cleanup; otherwise tcm_disable() can cancel the queued work and clean up immediately. Also serialize the final delayed-status completion with the cancellation check while holding the composite device lock. This prevents a disconnect from clearing delayed_status while the worker is about to complete the control request. Validation reproduced this kernel report: BUG: KASAN: slab-use-after-free in tcm_delayed_set_alt+0x6c/0xef0 Call Trace: <TASK> dump_stack_lvl+0x66/0xa0 print_report+0xce/0x630 ? tcm_delayed_set_alt+0x6c/0xef0 ? srso_alias_return_thunk+0x5/0xfbef5 ? __virt_addr_valid+0x188/0x320 ? tcm_delayed_set_alt+0x6c/0xef0 kasan_report+0xe0/0x110 ? tcm_delayed_set_alt+0x6c/0xef0 tcm_delayed_set_alt+0x6c/0xef0 ? __pfx_tcm_delayed_set_alt+0x10/0x10 ? process_one_work+0x4cb/0xb90 ? rcu_is_watching+0x20/0x50 ? tcm_delayed_set_alt+0x9/0xef0 process_one_work+0x4d7/0xb90 ? __pfx_process_one_work+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? __list_add_valid_or_report+0x37/0xf0 ? __pfx_tcm_delayed_set_alt+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 worker_thread+0x2d8/0x570 ? __pfx_worker_thread+0x10/0x10 kthread+0x1ad/0x1f0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x3c9/0x540 ? __pfx_ret_from_fork+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? __switch_to+0x2e9/0x730 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> Allocated by task 544: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x8f/0xa0 tcm_alloc+0x68/0x180 usb_get_function+0x36/0x60 config_usb_cfg_link+0x125/0x1b0 configfs_symlink+0x322/0x890 vfs_symlink+0xc2/0x270 filename_symlinkat+0x295/0x2f0 __x64_sys_symlinkat+0x62/0x90 do_syscall_64+0x115/0x6a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 661: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x43/0x70 kfree+0x2f9/0x530 config_usb_cfg_unlink+0x173/0x1e0 configfs_unlink+0x1fa/0x340 vfs_unlink+0x15c/0x510 filename_unlinkat+0x2ba/0x450 __x64_sys_unlinkat+0x63/0x90 do_syscall_64+0x115/0x6a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| Linux Linux |
≥ c52661d60f636d17e26ad834457db333bd1df494; < 8fb317058d165c88f3344f59439c14872c162b3c (affected, git) ≥ c52661d60f636d17e26ad834457db333bd1df494; < 90431d8523c0c1c9f8e3e3f0895727063f93da85 (affected, git) ≥ c52661d60f636d17e26ad834457db333bd1df494; < ee07d09419f1c59c74f73107aa08444f2f2fc6c8 (affected, git) ≥ c52661d60f636d17e26ad834457db333bd1df494; < 3118bb872c7dff653294f193d5328a476619e04d (affected, git) ≥ c52661d60f636d17e26ad834457db333bd1df494; < a6eb5a0ae7cd313cfd7df78decd8f43b64c68703 (affected, git) ≥ c52661d60f636d17e26ad834457db333bd1df494; < f282242906c12fd476b86757afba51f211d4f959 (affected, git) ≥ c52661d60f636d17e26ad834457db333bd1df494; < 4c6c6a5588b9a2f8437fb794e852d05fa60ebe53 (affected, git) ≥ c52661d60f636d17e26ad834457db333bd1df494; < 79e2d75725c85607f8a9d87ae9cace62a19f767d (affected, git) Other versions: unaffected |
CNA: Linux |
| Linux Linux |
3.5 (affected) ≥ 0; < 3.5 (unaffected, semver) ≥ 5.10.266; ≤ 5.10.* (unaffected, semver) ≥ 5.15.217; ≤ 5.15.* (unaffected, semver) ≥ 6.1.184; ≤ 6.1.* (unaffected, semver) ≥ 6.6.151; ≤ 6.6.* (unaffected, semver) ≥ 6.12.103; ≤ 6.12.* (unaffected, semver) ≥ 6.18.42; ≤ 6.18.* (unaffected, semver) ≥ 7.1.6; ≤ 7.1.* (unaffected, semver) ≥ 7.2; ≤ * (unaffected, original_commit_for_fix) Other versions: affected |
CNA: Linux |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
No CVSS assessment reported. An unscored record is not a low-severity determination.
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://git.kernel.org/stable/c/8fb317058d165c88f3344f59439c14872c162b3cCNA: Linux
- https://git.kernel.org/stable/c/90431d8523c0c1c9f8e3e3f0895727063f93da85CNA: Linux
- https://git.kernel.org/stable/c/ee07d09419f1c59c74f73107aa08444f2f2fc6c8CNA: Linux
- https://git.kernel.org/stable/c/3118bb872c7dff653294f193d5328a476619e04dCNA: Linux
- https://git.kernel.org/stable/c/a6eb5a0ae7cd313cfd7df78decd8f43b64c68703CNA: Linux
- https://git.kernel.org/stable/c/f282242906c12fd476b86757afba51f211d4f959CNA: Linux
- https://git.kernel.org/stable/c/4c6c6a5588b9a2f8437fb794e852d05fa60ebe53CNA: Linux
- https://git.kernel.org/stable/c/79e2d75725c85607f8a9d87ae9cace62a19f767dCNA: Linux
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