In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Fix NULL dereference in tb_remove_work()
There is a slight race between tb_remove_work() and tb_domain_remove()
which leads to dereferencing a NULL tb->root_switch pointer inside
tb_free_unplugged_xdomains():
Thread A Thread B
tb_remove_work()
tb_domain_remove()
mutex_lock(&tb->lock)
tb_stop()
/* doesn't cancel a running callback */
cancel_delayed_work(&tcm->remove_work)
...
tb_switch_remove(tb->root_switch)
tb->root_switch = NULL
mutex_unlock(&tb->lock)
mutex_lock(&tb->lock)
...
/* without checking ->root_switch */
tb_free_unplugged_xdomains(tb->root_switch)
mutex_unlock(&tb->lock)
Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without
holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains()
out of the &tb->lock section and the check for tb->root_switch, in
particular. It states:
For this reason separate removing the XDomain from the topology data
structures (where we need the lock) from unregistering the device from
the bus (where remove callbacks of the drivers are being called).
tb_free_unplugged_xdomains() belongs to the former group of functions
requiring the lock. And it also calls tb_xdomain_remove() which should
only be called with &tb->lock held.
Found by Linux Verification Center (linuxtesting.org) with Svace static
analysis tool.
thunderbolt: Fix NULL dereference in tb_remove_work()
There is a slight race between tb_remove_work() and tb_domain_remove()
which leads to dereferencing a NULL tb->root_switch pointer inside
tb_free_unplugged_xdomains():
Thread A Thread B
tb_remove_work()
tb_domain_remove()
mutex_lock(&tb->lock)
tb_stop()
/* doesn't cancel a running callback */
cancel_delayed_work(&tcm->remove_work)
...
tb_switch_remove(tb->root_switch)
tb->root_switch = NULL
mutex_unlock(&tb->lock)
mutex_lock(&tb->lock)
...
/* without checking ->root_switch */
tb_free_unplugged_xdomains(tb->root_switch)
mutex_unlock(&tb->lock)
Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without
holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains()
out of the &tb->lock section and the check for tb->root_switch, in
particular. It states:
For this reason separate removing the XDomain from the topology data
structures (where we need the lock) from unregistering the device from
the bus (where remove callbacks of the drivers are being called).
tb_free_unplugged_xdomains() belongs to the former group of functions
requiring the lock. And it also calls tb_xdomain_remove() which should
only be called with &tb->lock held.
Found by Linux Verification Center (linuxtesting.org) with Svace static
analysis tool.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Sun, 18 Oct 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: thunderbolt: Fix NULL dereference in tb_remove_work() There is a slight race between tb_remove_work() and tb_domain_remove() which leads to dereferencing a NULL tb->root_switch pointer inside tb_free_unplugged_xdomains(): Thread A Thread B tb_remove_work() tb_domain_remove() mutex_lock(&tb->lock) tb_stop() /* doesn't cancel a running callback */ cancel_delayed_work(&tcm->remove_work) ... tb_switch_remove(tb->root_switch) tb->root_switch = NULL mutex_unlock(&tb->lock) mutex_lock(&tb->lock) ... /* without checking ->root_switch */ tb_free_unplugged_xdomains(tb->root_switch) mutex_unlock(&tb->lock) Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains() out of the &tb->lock section and the check for tb->root_switch, in particular. It states: For this reason separate removing the XDomain from the topology data structures (where we need the lock) from unregistering the device from the bus (where remove callbacks of the drivers are being called). tb_free_unplugged_xdomains() belongs to the former group of functions requiring the lock. And it also calls tb_xdomain_remove() which should only be called with &tb->lock held. Found by Linux Verification Center (linuxtesting.org) with Svace static analysis tool. | |
| Title | thunderbolt: Fix NULL dereference in tb_remove_work() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-18T15:46:02.231Z
Reserved: 2026-09-25T10:25:14.364Z
Link: CVE-2026-98688
No data.
Status : Received
Published: 2026-10-18T16:17:22.207
Modified: 2026-10-18T16:17:22.207
Link: CVE-2026-98688
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.