Reserved commands will be used by SCSI LLDs for submitting internal
commands. Since the SCSI host, target and device limits do not apply to
the reserved command use cases, bypass the SCSI host limit checks for
reserved commands. Introduce the .queue_reserved_command() callback for
reserved commands. Additionally, do not activate the SCSI error handler
if a reserved command fails such that reserved commands can be submitted
from inside the SCSI error handler.
[ bvanassche: modified patch title and patch description. Renamed
.reserved_queuecommand() into .queue_reserved_command(). Changed
the second argument of __blk_mq_end_request() from 0 into error
code in the completion path if cmd->result != 0. Rewrote the
scsi_queue_rq() changes. See also
https://lore.kernel.org/linux-scsi/1666693096-180008-5-git-send-email-john.garry@huawei.com/ ]
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://patch.msgid.link/20251031204029.2883185-6-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Allocate a pseudo SCSI device if 'nr_reserved_cmds' has been set. Pseudo
SCSI devices have the SCSI ID <max_id>:U64_MAX so they won't clash with
any devices the LLD might create. Pseudo SCSI devices are excluded from
scanning and will not show up in sysfs. Additionally, pseudo SCSI
devices are skipped by shost_for_each_device(). This prevents that the
SCSI error handler tries to submit a reset to a non-existent logical
unit.
Do not allocate a budget map for pseudo SCSI devices since the
cmd_per_lun limit does not apply to pseudo SCSI devices.
Do not perform queue depth ramp up / ramp down for pseudo SCSI devices.
Pseudo SCSI devices will be used to send internal commands to a storage
device.
[ bvanassche: edited patch description / renamed host_sdev into
pseudo_sdev / unexported scsi_get_host_dev() / modified error path in
scsi_get_pseudo_dev() / skip pseudo devices in __scsi_iterate_devices()
and also when calling sdev_init(), sdev_configure() and sdev_destroy().
See also
https://lore.kernel.org/linux-scsi/20211125151048.103910-2-hare@suse.de/ ]
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251031204029.2883185-5-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Quite some drivers are using management commands internally. These
commands typically use the same tag pool as regular SCSI commands. Tags
for these management commands are set aside before allocating the
block-mq tag bitmap for regular SCSI commands. The block layer already
supports this via the reserved tag mechanism. Add a new field
'nr_reserved_cmds' to the SCSI host template to instruct the block layer
to set aside a tag space for these management commands by using reserved
tags. Exclude reserved commands from .can_queue because .can_queue is
visible in sysfs.
[ bvanassche: modified patch title and patch description. Left out the
following statements: "if (sht->nr_reserved_cmds)" and also
"if (sdev->host->nr_reserved_cmds) flags |= BLK_MQ_REQ_RESERVED;". Moved
nr_reserved_cmds declarations and statements close to the
corresponding can_queue declarations and statements. See also
https://lore.kernel.org/linux-scsi/20210503150333.130310-11-hare@suse.de/ ]
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251031204029.2883185-2-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Commit 995412e23b ("blk-mq: Replace tags->lock with SRCU for tag
iterators") introduced the following regression:
Call trace:
__srcu_read_lock+0x30/0x80 (P)
blk_mq_tagset_busy_iter+0x44/0x300
scsi_host_busy+0x38/0x70
ufshcd_print_host_state+0x34/0x1bc
ufshcd_link_startup.constprop.0+0xe4/0x2e0
ufshcd_init+0x944/0xf80
ufshcd_pltfrm_init+0x504/0x820
ufs_rockchip_probe+0x2c/0x88
platform_probe+0x5c/0xa4
really_probe+0xc0/0x38c
__driver_probe_device+0x7c/0x150
driver_probe_device+0x40/0x120
__driver_attach+0xc8/0x1e0
bus_for_each_dev+0x7c/0xdc
driver_attach+0x24/0x30
bus_add_driver+0x110/0x230
driver_register+0x68/0x130
__platform_driver_register+0x20/0x2c
ufs_rockchip_pltform_init+0x1c/0x28
do_one_initcall+0x60/0x1e0
kernel_init_freeable+0x248/0x2c4
kernel_init+0x20/0x140
ret_from_fork+0x10/0x20
Fix this regression by making scsi_host_busy() check whether the SCSI
host tag set has already been initialized. tag_set->ops is set by
scsi_mq_setup_tags() just before blk_mq_alloc_tag_set() is called. This
fix is based on the assumption that scsi_host_busy() and
scsi_mq_setup_tags() calls are serialized. This is the case in the UFS
driver.
Reported-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Closes: https://lore.kernel.org/linux-block/pnezafputodmqlpumwfbn644ohjybouveehcjhz2hmhtcf2rka@sdhoiivync4y/
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://patch.msgid.link/20251007214800.1678255-1-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The virt_boundary_mask limit requires an unlimited max_segment_size for
bio splitting to not corrupt data. Historically, the block layer tried
to validate this, although the check was half-hearted until the addition
of the atomic queue limits API. The full blown check then triggered
issues with stacked devices incorrectly inheriting limits such as the
virt boundary and got disabled in commit b561ea56a2 ("block: allow
device to have both virt_boundary_mask and max segment size") instead of
fixing the issue properly.
Ensure that the SCSI mid layer doesn't set the default low
max_segment_size limit for this case, and check for invalid
max_segment_size values in the host template, similar to the original
block layer check given that SCSI devices can't be stacked.
This fixes reported data corruption on storvsc, although as far as I can
tell storvsc always failed to properly set the max_segment_size limit as
the SCSI APIs historically applied that when setting up the host, while
storvsc only set the virt_boundary_mask when configuring the scsi_device.
Fixes: 81988a0e6b ("storvsc: get rid of bounce buffer")
Fixes: b561ea56a2 ("block: allow device to have both virt_boundary_mask and max segment size")
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250624125233.219635-3-hch@lst.de
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Pull SCSI updates from James Bottomley:
"Updates to the usual drivers (ufs, lpfc, qla2xxx, mpi3mr, libsas).
The major update (which causes a conflict with block, see below) is
Christoph removing the queue limits and their associated block
helpers.
The remaining patches are assorted minor fixes and deprecated function
updates plus a bit of constification"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (141 commits)
scsi: mpi3mr: Sanitise num_phys
scsi: lpfc: Copyright updates for 14.4.0.2 patches
scsi: lpfc: Update lpfc version to 14.4.0.2
scsi: lpfc: Add support for 32 byte CDBs
scsi: lpfc: Change lpfc_hba hba_flag member into a bitmask
scsi: lpfc: Introduce rrq_list_lock to protect active_rrq_list
scsi: lpfc: Clear deferred RSCN processing flag when driver is unloading
scsi: lpfc: Update logging of protection type for T10 DIF I/O
scsi: lpfc: Change default logging level for unsolicited CT MIB commands
scsi: target: Remove unused list 'device_list'
scsi: iscsi: Remove unused list 'connlist_err'
scsi: ufs: exynos: Add support for Tensor gs101 SoC
scsi: ufs: exynos: Add some pa_dbg_ register offsets into drvdata
scsi: ufs: exynos: Allow max frequencies up to 267Mhz
scsi: ufs: exynos: Add EXYNOS_UFS_OPT_TIMER_TICK_SELECT option
scsi: ufs: exynos: Add EXYNOS_UFS_OPT_UFSPR_SECURE option
scsi: ufs: dt-bindings: exynos: Add gs101 compatible
scsi: qla2xxx: Fix debugfs output for fw_resource_count
scsi: qedf: Ensure the copied buf is NUL terminated
scsi: bfa: Ensure the copied buf is NUL terminated
...
Commit fc663711b9 ("scsi: core: Remove the /proc/scsi/${proc_name}
directory earlier") fixed a bug related to modules loading/unloading, by
adding a call to scsi_proc_hostdir_rm() on scsi_remove_host(). But that led
to a potential duplicate call to the hostdir_rm() routine, since it's also
called from scsi_host_dev_release(). That triggered a regression report,
which was then fixed by commit be03df3d4b ("scsi: core: Fix a procfs host
directory removal regression"). The fix just dropped the hostdir_rm() call
from dev_release().
But it happens that this proc directory is created on scsi_host_alloc(),
and that function "pairs" with scsi_host_dev_release(), while
scsi_remove_host() pairs with scsi_add_host(). In other words, it seems the
reason for removing the proc directory on dev_release() was meant to cover
cases in which a SCSI host structure was allocated, but the call to
scsi_add_host() didn't happen. And that pattern happens to exist in some
error paths, for example.
Syzkaller causes that by using USB raw gadget device, error'ing on
usb-storage driver, at usb_stor_probe2(). By checking that path, we can see
that the BadDevice label leads to a scsi_host_put() after a SCSI host
allocation, but there's no call to scsi_add_host() in such path. That leads
to messages like this in dmesg (and a leak of the SCSI host proc
structure):
usb-storage 4-1:87.51: USB Mass Storage device detected
proc_dir_entry 'scsi/usb-storage' already registered
WARNING: CPU: 1 PID: 3519 at fs/proc/generic.c:377 proc_register+0x347/0x4e0 fs/proc/generic.c:376
The proper fix seems to still call scsi_proc_hostdir_rm() on dev_release(),
but guard that with the state check for SHOST_CREATED; there is even a
comment in scsi_host_dev_release() detailing that: such conditional is
meant for cases where the SCSI host was allocated but there was no calls to
{add,remove}_host(), like the usb-storage case.
This is what we propose here and with that, the error path of usb-storage
does not trigger the warning anymore.
Reported-by: syzbot+c645abf505ed21f931b5@syzkaller.appspotmail.com
Fixes: be03df3d4b ("scsi: core: Fix a procfs host directory removal regression")
Cc: stable@vger.kernel.org
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Link: https://lore.kernel.org/r/20240313113006.2834799-1-gpiccoli@igalia.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
There are two .exit_cmd_priv implementations. Both implementations use
resources associated with the SCSI host. Make sure that these resources are
still available when .exit_cmd_priv is called by waiting inside
scsi_remove_host() until the tag set has been freed.
This commit fixes the following use-after-free:
==================================================================
BUG: KASAN: use-after-free in srp_exit_cmd_priv+0x27/0xd0 [ib_srp]
Read of size 8 at addr ffff888100337000 by task multipathd/16727
Call Trace:
<TASK>
dump_stack_lvl+0x34/0x44
print_report.cold+0x5e/0x5db
kasan_report+0xab/0x120
srp_exit_cmd_priv+0x27/0xd0 [ib_srp]
scsi_mq_exit_request+0x4d/0x70
blk_mq_free_rqs+0x143/0x410
__blk_mq_free_map_and_rqs+0x6e/0x100
blk_mq_free_tag_set+0x2b/0x160
scsi_host_dev_release+0xf3/0x1a0
device_release+0x54/0xe0
kobject_put+0xa5/0x120
device_release+0x54/0xe0
kobject_put+0xa5/0x120
scsi_device_dev_release_usercontext+0x4c1/0x4e0
execute_in_process_context+0x23/0x90
device_release+0x54/0xe0
kobject_put+0xa5/0x120
scsi_disk_release+0x3f/0x50
device_release+0x54/0xe0
kobject_put+0xa5/0x120
disk_release+0x17f/0x1b0
device_release+0x54/0xe0
kobject_put+0xa5/0x120
dm_put_table_device+0xa3/0x160 [dm_mod]
dm_put_device+0xd0/0x140 [dm_mod]
free_priority_group+0xd8/0x110 [dm_multipath]
free_multipath+0x94/0xe0 [dm_multipath]
dm_table_destroy+0xa2/0x1e0 [dm_mod]
__dm_destroy+0x196/0x350 [dm_mod]
dev_remove+0x10c/0x160 [dm_mod]
ctl_ioctl+0x2c2/0x590 [dm_mod]
dm_ctl_ioctl+0x5/0x10 [dm_mod]
__x64_sys_ioctl+0xb4/0xf0
dm_ctl_ioctl+0x5/0x10 [dm_mod]
__x64_sys_ioctl+0xb4/0xf0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Link: https://lore.kernel.org/r/20220826002635.919423-1-bvanassche@acm.org
Fixes: 65ca846a53 ("scsi: core: Introduce {init,exit}_cmd_priv()")
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: John Garry <john.garry@huawei.com>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Reported-by: Li Zhijian <lizhijian@fujitsu.com>
Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Pull more SCSI updates from James Bottomley:
"Mostly small bug fixes and trivial updates.
The major new core update is a change to the way device, target and
host reference counting is done to try to make it more robust (this
change has soaked for a while to try to winkle out any bugs)"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: pm8001: Fix typo 'the the' in comment
scsi: megaraid_sas: Remove redundant variable cmd_type
scsi: FlashPoint: Remove redundant variable bm_int_st
scsi: zfcp: Fix missing auto port scan and thus missing target ports
scsi: core: Call blk_mq_free_tag_set() earlier
scsi: core: Simplify LLD module reference counting
scsi: core: Make sure that hosts outlive targets
scsi: core: Make sure that targets outlive devices
scsi: ufs: ufs-pci: Correct check for RESET DSM
scsi: target: core: De-RCU of se_lun and se_lun acl
scsi: target: core: Fix race during ACL removal
scsi: ufs: core: Correct ufshcd_shutdown() flow
scsi: ufs: core: Increase the maximum data buffer size
scsi: lpfc: Check the return value of alloc_workqueue()
