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authorThomas Gleixner <tglx@linutronix.de>2021-05-06 15:21:37 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2021-05-07 06:06:21 -0400
commit3f804f6d201ca93adf4c3df04d1bfd152c1129d6 (patch)
tree157c4afa56821edc51819324cdd118df21a7fd9f /virt
parent594b27e677b35f9734b1969d175ebc6146741109 (diff)
KVM: x86: Prevent deadlock against tk_core.seq
syzbot reported a possible deadlock in pvclock_gtod_notify(): CPU 0 CPU 1 write_seqcount_begin(&tk_core.seq); pvclock_gtod_notify() spin_lock(&pool->lock); queue_work(..., &pvclock_gtod_work) ktime_get() spin_lock(&pool->lock); do { seq = read_seqcount_begin(tk_core.seq) ... } while (read_seqcount_retry(&tk_core.seq, seq); While this is unlikely to happen, it's possible. Delegate queue_work() to irq_work() which postpones it until the tk_core.seq write held region is left and interrupts are reenabled. Fixes: 16e8d74d2da9 ("KVM: x86: notifier for clocksource changes") Reported-by: syzbot+6beae4000559d41d80f8@syzkaller.appspotmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Message-Id: <87h7jgm1zy.ffs@nanos.tec.linutronix.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
0 files changed, 0 insertions, 0 deletions