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block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user()#773

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block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user()#773
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@blktests-ci blktests-ci Bot commented Apr 27, 2026

Pull request for series with
subject: block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user()
version: 4
url: https://patchwork.kernel.org/project/linux-block/list/?series=1085839

pin_user_pages_fast() can partially succeed and return the number of
pages that were actually pinned. However, the bio_integrity_map_user()
does not handle this partial pinning. This leads to a general protection
fault since bvec_from_pages() dereferences an unpinned page address,
which is 0.

To fix this, add a check to verify that all requested memory is pinned.
If partial pinning occurs, unpin the memory and return -EFAULT.

Reproducer in blktest: linux-blktests/blktests#244

Kernel Oops:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 UID: 0 PID: 1061 Comm: nvme-passthroug Not tainted 7.0.0-11783-g90957f9314e8-dirty #16 PREEMPT(lazy)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
RIP: 0010:bio_integrity_map_user.cold+0x1b0/0x9d6

Fixes: 492c5d4 ("block: bio-integrity: directly map user buffers")
Acked-by: Chao Shi <[email protected]>
Acked-by: Weidong Zhu <[email protected]>
Acked-by: Dave Tian <[email protected]>
Signed-off-by: Sungwoo Kim <[email protected]>
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blktests-ci Bot commented Apr 27, 2026

Upstream branch: dd6c438
series: https://patchwork.kernel.org/project/linux-block/list/?series=1085839
version: 4

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