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CVE-2021-46939 is a deadlock vulnerability in the Linux kernel tracing subsystem. When tracing is recursively re-entered, including through the function graph tracer, trace_clock_global() can acquire the lock protecting its recorded previous timestamp while reserving a ring-buffer event. A traced operation can then re-enter ring_buffer_lock_reserve() and invoke trace_clock_global() again on the same execution path, causing a second attempt to acquire the already-held spinlock. The resulting deadlock can hang the machine. The upstream fix restructures trace_clock_global() to avoid blocking: it uses a trylock when updating the previous timestamp and defers the update if the lock is already held.
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Linux kernel tracing flaw corrected by ensuring trace_clock_global() does not block.
Linux kernel tracing issue addressed by preventing trace_clock_global() from blocking.
A Linux kernel tracing vulnerability involving trace_clock_global() potentially blocking; the referenced assessment characterizes the impact as moderate and associates it with lock/deadlock and tracing conditions.
A Linux kernel tracing deadlock vulnerability in trace_clock_global(). Recursive tracing can re-acquire an already-held spin lock, causing a system hang/denial of service. The fix restructures the code to use a trylock when updating prev_time so tracing does not block.
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Cross-references every affected SKU, including bundled OEM variants.
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