In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
acpi\/apei\/ghes: Use raw_spinlock_t for CXL CPER work locks<\/p>\n
The CXL CPER work registration and unregistration helpers acquire
\ncxl_cper_work_lock and cxl_cper_prot_err_work_lock with a spinlock
\nguard(), which leaves local interrupts enabled. The corresponding post
\npaths (cxl_cper_post_event(), cxl_cper_post_prot_err()) execute in hard
\nIRQ context (they are called from the GHES error notification path) and
\nacquire the same locks with an irqsave guard().<\/p>\n
If a CPU is holding one of these locks via a spinlock guard() when a GHES
\ninterrupt arrives on the same CPU, the IRQ handler spins on the held lock
\nwaiting for it to release, while the lock holder is preempted by the IRQ.
\nThe result is a deadlock.<\/p>\n
Convert both locks from spinlock_t to raw_spinlock_t and use guard() at
\nall call sites. On PREEMPT_RT kernels spinlock_t is backed by rt_mutex and
\nsleeping from hard IRQ context is not permitted; raw_spinlock_t is safe in
\nboth contexts.<\/p>\n
Add WARN_ONCE to both register functions to surface double-registration
\nbugs at runtime.<\/p>\n
Restructure both unregister functions to clear the global work pointer
\nunder the lock before calling cancel_work_sync(), closing the window
\nwhere a CPER interrupt could schedule work on a pointer about to be
\nfreed. Add kfifo_reset() after cancel_work_sync() so stale entries
\nare not replayed on next module load.<\/p>\n
Both kfifos are single-consumer: only one work_struct is registered at
\na time, enforced by the WARN_ONCE guard in the register functions.
\nkfifo_reset() is safe outside the lock because cancel_work_sync() has
\nalready quiesced the consumer, and no new consumer can register until
\nthe current module exit completes and a fresh module init runs.<\/p>\n
Remove the redundant cancel_work_sync() call from cxl_ras_exit() and
\ncxl_pci_driver_exit(). The CPER unregister functions now quiesce
\nthe work internally.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
acpi\/apei\/ghes: Use raw_spinlock_t for CXL CPER work locks<\/p>\n
The CXL CPER work registration and unregistration helpers acquire
\ncxl_c<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21511","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21511","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21511"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21511"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21511"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}