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Filename Latest commit message Latest commit date
Guilherme G. Piccoli 0053f15d50 scsi: core: Fix unremoved procfs host directory regression
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 <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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-13 12:51:32 +02:00
arch powerpc: xor_vmx: Add '-mhard-float' to CFLAGS 2024-04-13 12:51:31 +02:00
block block: sed-opal: handle empty atoms when parsing response 2024-03-26 18:22:12 -04:00
certs
crypto
Documentation x86/cpu: Support AMD Automatic IBRS 2024-04-13 12:51:21 +02:00
drivers scsi: core: Fix unremoved procfs host directory regression 2024-04-13 12:51:32 +02:00
fs exec: Fix NOMMU linux_binprm::exec in transfer_args_to_stack() 2024-04-13 12:51:31 +02:00
include objtool: Add support for intra-function calls 2024-04-13 12:51:29 +02:00
init
ipc
kernel bounds: support non-power-of-two CONFIG_NR_CPUS 2024-04-13 12:51:31 +02:00
lib net: blackhole_dev: fix build warning for ethh set but not used 2024-03-26 18:22:15 -04:00
LICENSES
mm mm/migrate: set swap entry values of THP tail pages properly. 2024-04-13 12:51:31 +02:00
net wifi: mac80211: check/clear fast rx for non-4addr sta VLAN changes 2024-04-13 12:51:31 +02:00
samples media: rename VFL_TYPE_GRABBER to _VIDEO 2024-03-26 18:22:22 -04:00
scripts kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1 2024-04-13 12:51:26 +02:00
security smack: Handle SMACK64TRANSMUTE in smack_inode_setsecurity() 2024-04-13 12:51:22 +02:00
sound ALSA: sh: aica: reorder cleanup operations to avoid UAF bugs 2024-04-13 12:51:32 +02:00
tools objtool: Add support for intra-function calls 2024-04-13 12:51:29 +02:00
usr
virt KVM: Always flush async #PF workqueue when vCPU is being destroyed 2024-04-13 12:51:22 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.273 2024-03-26 18:23:12 -04:00
README

Linux kernel
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There are several guides for kernel developers and users. These guides can
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There are various text files in the Documentation/ subdirectory,
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Please read the Documentation/process/changes.rst file, as it contains the
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