kernel.git/drivers/scsi/hosts.c, branch linux-5.4.y

scsi: core: Fix unremoved procfs host directory regression

2024-04-13T10:51:32Z

commit f23a4d6e07570826fe95023ca1aa96a011fa9f84 upstream. Commit fc663711b944 ("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 be03df3d4bfe ("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: be03df3d4bfe ("scsi: core: Fix a procfs host directory removal regression") Cc: stable@vger.kernel.org Cc: Bart Van Assche Cc: John Garry Cc: Shin'ichiro Kawasaki Signed-off-by: Guilherme G. Piccoli Link: https://lore.kernel.org/r/20240313113006.2834799-1-gpiccoli@igalia.com Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: core: Use 32-bit hostnum in scsi_host_lookup()

2023-09-23T08:59:51Z

[ Upstream commit 62ec2092095b678ff89ce4ba51c2938cd1e8e630 ] Change scsi_host_lookup() hostnum argument type from unsigned short to unsigned int to match the type used everywhere else. Fixes: 6d49f63b415c ("[SCSI] Make host_no an unsigned int") Signed-off-by: Tony Battersby Link: https://lore.kernel.org/r/a02497e7-c12b-ef15-47fc-3f0a0b00ffce@cybernetics.com Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

scsi: core: Fix a procfs host directory removal regression

2023-03-22T12:28:04Z

[ Upstream commit be03df3d4bfe7e8866d4aa43d62e648ffe884f5f ] scsi_proc_hostdir_rm() decreases a reference counter and hence must only be called once per host that is removed. This change does not require a scsi_add_host_with_dma() change since scsi_add_host_with_dma() will return 0 (success) if scsi_proc_host_add() is called. Fixes: fc663711b944 ("scsi: core: Remove the /proc/scsi/${proc_name} directory earlier") Cc: John Garry Reported-by: John Garry Link: https://lore.kernel.org/all/ed6b8027-a9d9-1b45-be8e-df4e8c6c4605@oracle.com/ Reported-by: syzbot+645a4616b87a2f10e398@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-scsi/000000000000890fab05f65342b6@google.com/ Signed-off-by: Bart Van Assche Link: https://lore.kernel.org/r/20230307214428.3703498-1-bvanassche@acm.org Tested-by: John Garry Tested-by: Shin'ichiro Kawasaki Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

scsi: core: Fix a comment in function scsi_host_dev_release()

2023-03-22T12:28:04Z

[ Upstream commit 2dde5c8d912efea43be94d6a83ac9cb74879fa12 ] Commit 3be8828fc507 ("scsi: core: Avoid that ATA error handling can trigger a kernel hang or oops") moved rcu to scsi_cmnd instead of shost. Modify "shost->rcu" to "scmd->rcu" in a comment. Link: https://lore.kernel.org/r/1620646526-193154-1-git-send-email-chenxiang66@hisilicon.com Signed-off-by: Xiang Chen Signed-off-by: Martin K. Petersen Stable-dep-of: be03df3d4bfe ("scsi: core: Fix a procfs host directory removal regression") Signed-off-by: Sasha Levin

scsi: core: Remove the /proc/scsi/${proc_name} directory earlier

2023-03-17T07:32:50Z

[ Upstream commit fc663711b94468f4e1427ebe289c9f05669699c9 ] Remove the /proc/scsi/${proc_name} directory earlier to fix a race condition between unloading and reloading kernel modules. This fixes a bug introduced in 2009 by commit 77c019768f06 ("[SCSI] fix /proc memory leak in the SCSI core"). Fix the following kernel warning: proc_dir_entry 'scsi/scsi_debug' already registered WARNING: CPU: 19 PID: 27986 at fs/proc/generic.c:376 proc_register+0x27d/0x2e0 Call Trace: proc_mkdir+0xb5/0xe0 scsi_proc_hostdir_add+0xb5/0x170 scsi_host_alloc+0x683/0x6c0 sdebug_driver_probe+0x6b/0x2d0 [scsi_debug] really_probe+0x159/0x540 __driver_probe_device+0xdc/0x230 driver_probe_device+0x4f/0x120 __device_attach_driver+0xef/0x180 bus_for_each_drv+0xe5/0x130 __device_attach+0x127/0x290 device_initial_probe+0x17/0x20 bus_probe_device+0x110/0x130 device_add+0x673/0xc80 device_register+0x1e/0x30 sdebug_add_host_helper+0x1a7/0x3b0 [scsi_debug] scsi_debug_init+0x64f/0x1000 [scsi_debug] do_one_initcall+0xd7/0x470 do_init_module+0xe7/0x330 load_module+0x122a/0x12c0 __do_sys_finit_module+0x124/0x1a0 __x64_sys_finit_module+0x46/0x50 do_syscall_64+0x38/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Link: https://lore.kernel.org/r/20230210205200.36973-3-bvanassche@acm.org Cc: Alan Stern Cc: Yi Zhang Cc: stable@vger.kernel.org Fixes: 77c019768f06 ("[SCSI] fix /proc memory leak in the SCSI core") Reported-by: Yi Zhang Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

scsi: core: Fix shost->cmd_per_lun calculation in scsi_add_host_with_dma()

2021-10-27T07:54:29Z

commit 50b6cb3516365cb69753b006be2b61c966b70588 upstream. After commit ea2f0f77538c ("scsi: core: Cap scsi_host cmd_per_lun at can_queue"), a 416-CPU VM running on Hyper-V hangs during boot because the hv_storvsc driver sets scsi_driver.can_queue to an integer value that exceeds SHRT_MAX, and hence scsi_add_host_with_dma() sets shost->cmd_per_lun to a negative "short" value. Use min_t(int, ...) to work around the issue. Link: https://lore.kernel.org/r/20211008043546.6006-1-decui@microsoft.com Fixes: ea2f0f77538c ("scsi: core: Cap scsi_host cmd_per_lun at can_queue") Cc: stable@vger.kernel.org Reviewed-by: Haiyang Zhang Reviewed-by: Ming Lei Reviewed-by: John Garry Signed-off-by: Dexuan Cui Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: core: Cap scsi_host cmd_per_lun at can_queue

2021-07-20T14:10:42Z

[ Upstream commit ea2f0f77538c50739b9fb4de4700cee5535e1f77 ] The sysfs handling function sdev_store_queue_depth() enforces that the sdev queue depth cannot exceed shost can_queue. The initial sdev queue depth comes from shost cmd_per_lun. However, the LLDD may manually set cmd_per_lun to be larger than can_queue, which leads to an initial sdev queue depth greater than can_queue. Such an issue was reported in [0], which caused a hang. That has since been fixed in commit fc09acb7de31 ("scsi: scsi_debug: Fix cmd_per_lun, set to max_queue"). Stop this possibly happening for other drivers by capping shost cmd_per_lun at shost can_queue. [0] https://lore.kernel.org/linux-scsi/YHaez6iN2HHYxYOh@T590/ Link: https://lore.kernel.org/r/1621434662-173079-1-git-send-email-john.garry@huawei.com Reviewed-by: Ming Lei Reviewed-by: Bart Van Assche Signed-off-by: John Garry Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

scsi: core: Fix bad pointer dereference when ehandler kthread is invalid

2021-07-20T14:10:40Z

commit 93aa71ad7379900e61c8adff6a710a4c18c7c99b upstream. Commit 66a834d09293 ("scsi: core: Fix error handling of scsi_host_alloc()") changed the allocation logic to call put_device() to perform host cleanup with the assumption that IDA removal and stopping the kthread would properly be performed in scsi_host_dev_release(). However, in the unlikely case that the error handler thread fails to spawn, shost->ehandler is set to ERR_PTR(-ENOMEM). The error handler cleanup code in scsi_host_dev_release() will call kthread_stop() if shost->ehandler != NULL which will always be the case whether the kthread was successfully spawned or not. In the case that it failed to spawn this has the nasty side effect of trying to dereference an invalid pointer when kthread_stop() is called. The following splat provides an example of this behavior in the wild: scsi host11: error handler thread failed to spawn, error = -4 Kernel attempted to read user page (10c) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x0000010c Faulting instruction address: 0xc00000000818e9a8 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: ibmvscsi(+) scsi_transport_srp dm_multipath dm_mirror dm_region hash dm_log dm_mod fuse overlay squashfs loop CPU: 12 PID: 274 Comm: systemd-udevd Not tainted 5.13.0-rc7 #1 NIP: c00000000818e9a8 LR: c0000000089846e8 CTR: 0000000000007ee8 REGS: c000000037d12ea0 TRAP: 0300 Not tainted (5.13.0-rc7) MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 28228228 XER: 20040001 CFAR: c0000000089846e4 DAR: 000000000000010c DSISR: 40000000 IRQMASK: 0 GPR00: c0000000089846e8 c000000037d13140 c000000009cc1100 fffffffffffffffc GPR04: 0000000000000001 0000000000000000 0000000000000000 c000000037dc0000 GPR08: 0000000000000000 c000000037dc0000 0000000000000001 00000000fffff7ff GPR12: 0000000000008000 c00000000a049000 c000000037d13d00 000000011134d5a0 GPR16: 0000000000001740 c0080000190d0000 c0080000190d1740 c000000009129288 GPR20: c000000037d13bc0 0000000000000001 c000000037d13bc0 c0080000190b7898 GPR24: c0080000190b7708 0000000000000000 c000000033bb2c48 0000000000000000 GPR28: c000000046b28280 0000000000000000 000000000000010c fffffffffffffffc NIP [c00000000818e9a8] kthread_stop+0x38/0x230 LR [c0000000089846e8] scsi_host_dev_release+0x98/0x160 Call Trace: [c000000033bb2c48] 0xc000000033bb2c48 (unreliable) [c0000000089846e8] scsi_host_dev_release+0x98/0x160 [c00000000891e960] device_release+0x60/0x100 [c0000000087e55c4] kobject_release+0x84/0x210 [c00000000891ec78] put_device+0x28/0x40 [c000000008984ea4] scsi_host_alloc+0x314/0x430 [c0080000190b38bc] ibmvscsi_probe+0x54/0xad0 [ibmvscsi] [c000000008110104] vio_bus_probe+0xa4/0x4b0 [c00000000892a860] really_probe+0x140/0x680 [c00000000892aefc] driver_probe_device+0x15c/0x200 [c00000000892b63c] device_driver_attach+0xcc/0xe0 [c00000000892b740] __driver_attach+0xf0/0x200 [c000000008926f28] bus_for_each_dev+0xa8/0x130 [c000000008929ce4] driver_attach+0x34/0x50 [c000000008928fc0] bus_add_driver+0x1b0/0x300 [c00000000892c798] driver_register+0x98/0x1a0 [c00000000810eb60] __vio_register_driver+0x80/0xe0 [c0080000190b4a30] ibmvscsi_module_init+0x9c/0xdc [ibmvscsi] [c0000000080121d0] do_one_initcall+0x60/0x2d0 [c000000008261abc] do_init_module+0x7c/0x320 [c000000008265700] load_module+0x2350/0x25b0 [c000000008265cb4] __do_sys_finit_module+0xd4/0x160 [c000000008031110] system_call_exception+0x150/0x2d0 [c00000000800d35c] system_call_common+0xec/0x278 Fix this be nulling shost->ehandler when the kthread fails to spawn. Link: https://lore.kernel.org/r/20210701195659.3185475-1-tyreld@linux.ibm.com Fixes: 66a834d09293 ("scsi: core: Fix error handling of scsi_host_alloc()") Cc: stable@vger.kernel.org Reviewed-by: Ming Lei Signed-off-by: Tyrel Datwyler Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: core: Only put parent device if host state differs from SHOST_CREATED

2021-06-16T09:59:45Z

commit 1e0d4e6225996f05271de1ebcb1a7c9381af0b27 upstream. get_device(shost->shost_gendev.parent) is called after host state has switched to SHOST_RUNNING. scsi_host_dev_release() shouldn't release the parent device if host state is still SHOST_CREATED. Link: https://lore.kernel.org/r/20210602133029.2864069-5-ming.lei@redhat.com Cc: Bart Van Assche Cc: John Garry Cc: Hannes Reinecke Tested-by: John Garry Reviewed-by: John Garry Signed-off-by: Ming Lei Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: core: Put .shost_dev in failure path if host state changes to RUNNING

2021-06-16T09:59:45Z

commit 11714026c02d613c30a149c3f4c4a15047744529 upstream. scsi_host_dev_release() only frees dev_name when host state is SHOST_CREATED. After host state has changed to SHOST_RUNNING, scsi_host_dev_release() no longer cleans up. Fix this by doing a put_device(&shost->shost_dev) in the failure path when host state is SHOST_RUNNING. Move get_device(&shost->shost_gendev) before device_add(&shost->shost_dev) so that scsi_host_cls_release() can do a put on this reference. Link: https://lore.kernel.org/r/20210602133029.2864069-4-ming.lei@redhat.com Cc: Bart Van Assche Cc: Hannes Reinecke Reported-by: John Garry Tested-by: John Garry Reviewed-by: John Garry Reviewed-by: Hannes Reinecke Signed-off-by: Ming Lei Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman