Index: head/sys/kern/vfs_bio.c =================================================================== --- head/sys/kern/vfs_bio.c +++ head/sys/kern/vfs_bio.c @@ -4310,6 +4310,8 @@ extern int inflight_transient_maps; +static struct bio_queue nondump_bios; + void biodone(struct bio *bp) { @@ -4318,6 +4320,17 @@ vm_offset_t start, end; biotrack(bp, __func__); + + /* + * Avoid completing I/O when dumping after a panic since that may + * result in a deadlock in the filesystem or pager code. Note that + * this doesn't affect dumps that were started manually since we aim + * to keep the system usable after it has been resumed. + */ + if (__predict_false(dumping && SCHEDULER_STOPPED())) { + TAILQ_INSERT_HEAD(&nondump_bios, bp, bio_queue); + return; + } if ((bp->bio_flags & BIO_TRANSIENT_MAPPING) != 0) { bp->bio_flags &= ~BIO_TRANSIENT_MAPPING; bp->bio_flags |= BIO_UNMAPPED;