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ZIL: Fix another use-after-free.

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lwb->lwb_issued_txg can not be accessed after lwb_state is set to
LWB_STATE_FLUSH_DONE and zl_lock is dropped, since the lwb may be
freed by zil_sync().  We must save the txg number before that.

This is similar to the 55b1842f92, but as I see the bug is not new.
It existed for quite a while, just was not triggered due to smaller
race window.

Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #14988
Closes #14999
This commit is contained in:
Alexander Motin 2023-06-27 20:03:37 -04:00 committed by GitHub
parent b0cbc1aa9a
commit a9d6b0690b
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1 changed files with 1 additions and 1 deletions
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2
module/zfs/zil.c
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@ -1425,6 +1425,7 @@ zil_lwb_flush_vdevs_done(zio_t *zio)
list_move_tail(&itxs, &lwb->lwb_itxs);
list_move_tail(&waiters, &lwb->lwb_waiters);
txg = lwb->lwb_issued_txg;
ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE);
lwb->lwb_state = LWB_STATE_FLUSH_DONE;
@ -1465,7 +1466,6 @@ zil_lwb_flush_vdevs_done(zio_t *zio)
list_destroy(&waiters);
mutex_enter(&zilog->zl_lwb_io_lock);
txg = lwb->lwb_issued_txg;
ASSERT3U(zilog->zl_lwb_inflight[txg & TXG_MASK], >, 0);
zilog->zl_lwb_inflight[txg & TXG_MASK]--;
if (zilog->zl_lwb_inflight[txg & TXG_MASK] == 0)