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Mathieu Desnoyers authored
The rseq.h UAPI now documents that the rseq_cs field must be cleared before reclaiming memory that contains the targeted struct rseq_cs, but also that the rseq_cs field must be cleared before reclaiming memory of the code pointed to by the rseq_cs start_ip and post_commit_offset fields. While we can expect that use of dlclose(3) will typically unmap both struct rseq_cs and its associated code at once, nothing would theoretically prevent a JIT from reclaiming the code without reclaiming the struct rseq_cs, which would erroneously allow the kernel to consider new code which is not a rseq critical section as a rseq critical section following a code reclaim. Suggested-by:
Florian Weimer <fw@deneb.enyo.de> Signed-off-by:
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Florian Weimer <fw@deneb.enyo.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: "Paul E. McKenney" <paulmck@linux.ibm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Paul Turner <pjt@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
Shuah Khan <skhan@linuxfoundation.org>
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