In the Linux kernel, the following vulnerability has been resolved:
btrfs: use latest_dev in btrfs_show_devname
The test case btrfs/238 reports the warning below:
WARNING: CPU: 3 PID: 481 at fs/btrfs/super.c:2509 btrfs_show_devname+0x104/0x1e8 [btrfs]
CPU: 2 PID: 1 Comm: systemd Tainted: G W O 5.14.0-rc1-custom #72
Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
Call trace:
btrfs_show_devname+0x108/0x1b4 [btrfs]
show_mountinfo+0x234/0x2c4
m_show+0x28/0x34
seq_read_iter+0x12c/0x3c4
vfs_read+0x29c/0x2c8
ksys_read+0x80/0xec
__arm64_sys_read+0x28/0x34
invoke_syscall+0x50/0xf8
do_el0_svc+0x88/0x138
el0_svc+0x2c/0x8c
el0t_64_sync_handler+0x84/0xe4
el0t_64_sync+0x198/0x19c
Reason:
While btrfs_prepare_sprout() moves the fs_devices::devices into
fs_devices::seed_list, the btrfs_show_devname() searches for the devices
and found none, leading to the warning as in above.
Fix:
latest_dev is updated according to the changes to the device list.
That means we could use the latest_dev->name to show the device name in
/proc/self/mounts, the pointer will be always valid as it's assigned
before the device is deleted from the list in remove or replace.
The RCU protection is sufficient as the device structure is freed after
synchronization.
In the Linux kernel, the following vulnerability has been resolved:
dm btree remove: fix use after free in rebalance_children()
Move dm_tm_unlock() after dm_tm_dec().
In the Linux kernel, the following vulnerability has been resolved:
scsi: scsi_debug: Don't call kcalloc() if size arg is zero
If the size arg to kcalloc() is zero, it returns ZERO_SIZE_PTR. Because of
that, for a following NULL pointer check to work on the returned pointer,
kcalloc() must not be called with the size arg equal to zero. Return early
without error before the kcalloc() call if size arg is zero.
BUG: KASAN: null-ptr-deref in memcpy include/linux/fortify-string.h:191 [inline]
BUG: KASAN: null-ptr-deref in sg_copy_buffer+0x138/0x240 lib/scatterlist.c:974
Write of size 4 at addr 0000000000000010 by task syz-executor.1/22789
CPU: 1 PID: 22789 Comm: syz-executor.1 Not tainted 5.15.0-syzk #1
Hardware name: Red Hat KVM, BIOS 1.13.0-2
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x89/0xb5 lib/dump_stack.c:106
__kasan_report mm/kasan/report.c:446 [inline]
kasan_report.cold.14+0x112/0x117 mm/kasan/report.c:459
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x1a3/0x210 mm/kasan/generic.c:189
memcpy+0x3b/0x60 mm/kasan/shadow.c:66
memcpy include/linux/fortify-string.h:191 [inline]
sg_copy_buffer+0x138/0x240 lib/scatterlist.c:974
do_dout_fetch drivers/scsi/scsi_debug.c:2954 [inline]
do_dout_fetch drivers/scsi/scsi_debug.c:2946 [inline]
resp_verify+0x49e/0x930 drivers/scsi/scsi_debug.c:4276
schedule_resp+0x4d8/0x1a70 drivers/scsi/scsi_debug.c:5478
scsi_debug_queuecommand+0x8c9/0x1ec0 drivers/scsi/scsi_debug.c:7533
scsi_dispatch_cmd drivers/scsi/scsi_lib.c:1520 [inline]
scsi_queue_rq+0x16b0/0x2d40 drivers/scsi/scsi_lib.c:1699
blk_mq_dispatch_rq_list+0xb9b/0x2700 block/blk-mq.c:1639
__blk_mq_sched_dispatch_requests+0x28f/0x590 block/blk-mq-sched.c:325
blk_mq_sched_dispatch_requests+0x105/0x190 block/blk-mq-sched.c:358
__blk_mq_run_hw_queue+0xe5/0x150 block/blk-mq.c:1761
__blk_mq_delay_run_hw_queue+0x4f8/0x5c0 block/blk-mq.c:1838
blk_mq_run_hw_queue+0x18d/0x350 block/blk-mq.c:1891
blk_mq_sched_insert_request+0x3db/0x4e0 block/blk-mq-sched.c:474
blk_execute_rq_nowait+0x16b/0x1c0 block/blk-exec.c:62
blk_execute_rq+0xdb/0x360 block/blk-exec.c:102
sg_scsi_ioctl drivers/scsi/scsi_ioctl.c:621 [inline]
scsi_ioctl+0x8bb/0x15c0 drivers/scsi/scsi_ioctl.c:930
sg_ioctl_common+0x172d/0x2710 drivers/scsi/sg.c:1112
sg_ioctl+0xa2/0x180 drivers/scsi/sg.c:1165
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x19d/0x220 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3a/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
In the Linux kernel, the following vulnerability has been resolved:
ALSA: Fix deadlocks with kctl removals at disconnection
In snd_card_disconnect(), we set card->shutdown flag at the beginning,
call callbacks and do sync for card->power_ref_sleep waiters at the
end. The callback may delete a kctl element, and this can lead to a
deadlock when the device was in the suspended state. Namely:
* A process waits for the power up at snd_power_ref_and_wait() in
snd_ctl_info() or read/write() inside card->controls_rwsem.
* The system gets disconnected meanwhile, and the driver tries to
delete a kctl via snd_ctl_remove*(); it tries to take
card->controls_rwsem again, but this is already locked by the
above. Since the sleeper isn't woken up, this deadlocks.
An easy fix is to wake up sleepers before processing the driver
disconnect callbacks but right after setting the card->shutdown flag.
Then all sleepers will abort immediately, and the code flows again.
So, basically this patch moves the wait_event() call at the right
timing. While we're at it, just to be sure, call wait_event_all()
instead of wait_event(), although we don't use exclusive events on
this queue for now.
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix potential hang in nilfs_detach_log_writer()
Syzbot has reported a potential hang in nilfs_detach_log_writer() called
during nilfs2 unmount.
Analysis revealed that this is because nilfs_segctor_sync(), which
synchronizes with the log writer thread, can be called after
nilfs_segctor_destroy() terminates that thread, as shown in the call trace
below:
nilfs_detach_log_writer
nilfs_segctor_destroy
nilfs_segctor_kill_thread --> Shut down log writer thread
flush_work
nilfs_iput_work_func
nilfs_dispose_list
iput
nilfs_evict_inode
nilfs_transaction_commit
nilfs_construct_segment (if inode needs sync)
nilfs_segctor_sync --> Attempt to synchronize with
log writer thread
*** DEADLOCK ***
Fix this issue by changing nilfs_segctor_sync() so that the log writer
thread returns normally without synchronizing after it terminates, and by
forcing tasks that are already waiting to complete once after the thread
terminates.
The skipped inode metadata flushout will then be processed together in the
subsequent cleanup work in nilfs_segctor_destroy().
In the Linux kernel, the following vulnerability has been resolved:
net: bridge: xmit: make sure we have at least eth header len bytes
syzbot triggered an uninit value[1] error in bridge device's xmit path
by sending a short (less than ETH_HLEN bytes) skb. To fix it check if
we can actually pull that amount instead of assuming.
Tested with dropwatch:
drop at: br_dev_xmit+0xb93/0x12d0 [bridge] (0xffffffffc06739b3)
origin: software
timestamp: Mon May 13 11:31:53 2024 778214037 nsec
protocol: 0x88a8
length: 2
original length: 2
drop reason: PKT_TOO_SMALL
[1]
BUG: KMSAN: uninit-value in br_dev_xmit+0x61d/0x1cb0 net/bridge/br_device.c:65
br_dev_xmit+0x61d/0x1cb0 net/bridge/br_device.c:65
__netdev_start_xmit include/linux/netdevice.h:4903 [inline]
netdev_start_xmit include/linux/netdevice.h:4917 [inline]
xmit_one net/core/dev.c:3531 [inline]
dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3547
__dev_queue_xmit+0x34db/0x5350 net/core/dev.c:4341
dev_queue_xmit include/linux/netdevice.h:3091 [inline]
__bpf_tx_skb net/core/filter.c:2136 [inline]
__bpf_redirect_common net/core/filter.c:2180 [inline]
__bpf_redirect+0x14a6/0x1620 net/core/filter.c:2187
____bpf_clone_redirect net/core/filter.c:2460 [inline]
bpf_clone_redirect+0x328/0x470 net/core/filter.c:2432
___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
__bpf_prog_run512+0xb5/0xe0 kernel/bpf/core.c:2238
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
bpf_test_run+0x499/0xc30 net/bpf/test_run.c:425
bpf_prog_test_run_skb+0x14ea/0x1f20 net/bpf/test_run.c:1058
bpf_prog_test_run+0x6b7/0xad0 kernel/bpf/syscall.c:4269
__sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5678
__do_sys_bpf kernel/bpf/syscall.c:5767 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5765 [inline]
__x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5765
x64_sys_call+0x96b/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:322
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix division by zero in setup_dsc_config
When slice_height is 0, the division by slice_height in the calculation
of the number of slices will cause a division by zero driver crash. This
leaves the kernel in a state that requires a reboot. This patch adds a
check to avoid the division by zero.
The stack trace below is for the 6.8.4 Kernel. I reproduced the issue on
a Z16 Gen 2 Lenovo Thinkpad with a Apple Studio Display monitor
connected via Thunderbolt. The amdgpu driver crashed with this exception
when I rebooted the system with the monitor connected.
kernel: ? die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434 arch/x86/kernel/dumpstack.c:447)
kernel: ? do_trap (arch/x86/kernel/traps.c:113 arch/x86/kernel/traps.c:154)
kernel: ? setup_dsc_config (drivers/gpu/drm/amd/amdgpu/../display/dc/dsc/dc_dsc.c:1053) amdgpu
kernel: ? do_error_trap (./arch/x86/include/asm/traps.h:58 arch/x86/kernel/traps.c:175)
kernel: ? setup_dsc_config (drivers/gpu/drm/amd/amdgpu/../display/dc/dsc/dc_dsc.c:1053) amdgpu
kernel: ? exc_divide_error (arch/x86/kernel/traps.c:194 (discriminator 2))
kernel: ? setup_dsc_config (drivers/gpu/drm/amd/amdgpu/../display/dc/dsc/dc_dsc.c:1053) amdgpu
kernel: ? asm_exc_divide_error (./arch/x86/include/asm/idtentry.h:548)
kernel: ? setup_dsc_config (drivers/gpu/drm/amd/amdgpu/../display/dc/dsc/dc_dsc.c:1053) amdgpu
kernel: dc_dsc_compute_config (drivers/gpu/drm/amd/amdgpu/../display/dc/dsc/dc_dsc.c:1109) amdgpu
After applying this patch, the driver no longer crashes when the monitor
is connected and the system is rebooted. I believe this is the same
issue reported for 3113.