vdev_disk: don't touch vbio after its handed off to the kernel
After IO is unplugged, it may complete immediately and vbio_completion be called on interrupt context. That may interrupt or deschedule our task. If its the last bio, the vbio will be freed. Then, we get rescheduled, and try to write to freed memory through vbio->. This patch just removes the the cleanup, and the corresponding assert. These were leftovers from a previous iteration of vbio_submit() and were always "belt and suspenders" ops anyway, never strictly required. Sponsored-by: Klara, Inc. Sponsored-by: Wasabi Technology, Inc Reported-by: Rich Ercolani <rincebrain@gmail.com> Reviewed-by: Laurențiu Nicola <lnicola@dend.ro> Reviewed-by: Alexander Motin <mav@FreeBSD.org> Reviewed-by: George Wilson <george.wilson@delphix.com> Signed-off-by: Rob Norris <rob.norris@klarasystems.com> Closes #16045 Closes #16050 Closes #16049
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@ -755,8 +755,6 @@ vbio_fill_cb(struct page *page, size_t off, size_t len, void *priv)
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static void
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vbio_submit(vbio_t *vbio, abd_t *abd, uint64_t size)
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{
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ASSERT(vbio->vbio_bdev);
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/*
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* We plug so we can submit the BIOs as we go and only unplug them when
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* they are fully created and submitted. This is important; if we don't
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@ -774,12 +772,15 @@ vbio_submit(vbio_t *vbio, abd_t *abd, uint64_t size)
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vbio->vbio_bio->bi_end_io = vbio_completion;
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vbio->vbio_bio->bi_private = vbio;
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/*
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* Once submitted, vbio_bio now owns vbio (through bi_private) and we
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* can't touch it again. The bio may complete and vbio_completion() be
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* called and free the vbio before this task is run again, so we must
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* consider it invalid from this point.
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*/
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vdev_submit_bio(vbio->vbio_bio);
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blk_finish_plug(&plug);
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vbio->vbio_bio = NULL;
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vbio->vbio_bdev = NULL;
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}
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/* IO completion callback */
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