From: Damien Le Moal <dlemoal@kernel.org> mainline inclusion from mainline-v7.0-rc1 commit eddb98ad9364b4e778768785d46cfab04ce52100 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15109 CVE: CVE-2026-45855 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- A deferred qc may timeout while waiting for the device queue to drain to be submitted. In such case, since the qc is not active, ata_scsi_cmd_error_handler() ends up calling scsi_eh_finish_cmd(), which frees the qc. But as the port deferred_qc field still references this finished/freed qc, the deferred qc work may eventually attempt to call ata_qc_issue() against this invalid qc, leading to errors such as reported by UBSAN (syzbot run): UBSAN: shift-out-of-bounds in drivers/ata/libata-core.c:5166:24 shift exponent 4210818301 is too large for 64-bit type 'long long unsigned int' ... Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233 __ubsan_handle_shift_out_of_bounds+0x279/0x2a0 lib/ubsan.c:494 ata_qc_issue.cold+0x38/0x9f drivers/ata/libata-core.c:5166 ata_scsi_deferred_qc_work+0x154/0x1f0 drivers/ata/libata-scsi.c:1679 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> Fix this by checking if the qc of a timed out SCSI command is a deferred one, and in such case, clear the port deferred_qc field and finish the SCSI command with DID_TIME_OUT. Reported-by: syzbot+1f77b8ca15336fff21ff@syzkaller.appspotmail.com Fixes: 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ command starvation") Signed-off-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Igor Pylypiv <ipylypiv@google.com> Signed-off-by: Long Li <leo.lilong@huawei.com> --- drivers/ata/libata-eh.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c index a5caaf531ec7..8c7d7e993bbc 100644 --- a/drivers/ata/libata-eh.c +++ b/drivers/ata/libata-eh.c @@ -627,12 +627,28 @@ void ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap, set_host_byte(scmd, DID_OK); ata_qc_for_each_raw(ap, qc, i) { - if (qc->flags & ATA_QCFLAG_ACTIVE && - qc->scsicmd == scmd) + if (qc->scsicmd != scmd) + continue; + if ((qc->flags & ATA_QCFLAG_ACTIVE) || + qc == ap->deferred_qc) break; } - if (i < ATA_MAX_QUEUE) { + if (qc == ap->deferred_qc) { + /* + * This is a deferred command that timed out while + * waiting for the command queue to drain. Since the qc + * is not active yet (deferred_qc is still set, so the + * deferred qc work has not issued the command yet), + * simply signal the timeout by finishing the SCSI + * command and clear the deferred qc to prevent the + * deferred qc work from issuing this qc. + */ + WARN_ON_ONCE(qc->flags & ATA_QCFLAG_ACTIVE); + ap->deferred_qc = NULL; + set_host_byte(scmd, DID_TIME_OUT); + scsi_eh_finish_cmd(scmd, &ap->eh_done_q); + } else if (i < ATA_MAX_QUEUE) { /* the scmd has an associated qc */ if (!(qc->flags & ATA_QCFLAG_EH)) { /* which hasn't failed yet, timeout */ -- 2.52.0