| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
mm/swapfile: add cond_resched() in get_swap_pages()
The softlockup still occurs in get_swap_pages() under memory pressure. 64
CPU cores, 64GB memory, and 28 zram devices, the disksize of each zram
device is 50MB with same priority as si. Use the stress-ng tool to
increase memory pressure, causing the system to oom frequently.
The plist_for_each_entry_safe() loops in get_swap_pages() could reach tens
of thousands of times to find available space (extreme case:
cond_resched() is not called in scan_swap_map_slots()). Let's add
cond_resched() into get_swap_pages() when failed to find available space
to avoid softlockup. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix deadlock between concurrent dio writes when low on free data space
When reserving data space for a direct IO write we can end up deadlocking
if we have multiple tasks attempting a write to the same file range, there
are multiple extents covered by that file range, we are low on available
space for data and the writes don't expand the inode's i_size.
The deadlock can happen like this:
1) We have a file with an i_size of 1M, at offset 0 it has an extent with
a size of 128K and at offset 128K it has another extent also with a
size of 128K;
2) Task A does a direct IO write against file range [0, 256K), and because
the write is within the i_size boundary, it takes the inode's lock (VFS
level) in shared mode;
3) Task A locks the file range [0, 256K) at btrfs_dio_iomap_begin(), and
then gets the extent map for the extent covering the range [0, 128K).
At btrfs_get_blocks_direct_write(), it creates an ordered extent for
that file range ([0, 128K));
4) Before returning from btrfs_dio_iomap_begin(), it unlocks the file
range [0, 256K);
5) Task A executes btrfs_dio_iomap_begin() again, this time for the file
range [128K, 256K), and locks the file range [128K, 256K);
6) Task B starts a direct IO write against file range [0, 256K) as well.
It also locks the inode in shared mode, as it's within the i_size limit,
and then tries to lock file range [0, 256K). It is able to lock the
subrange [0, 128K) but then blocks waiting for the range [128K, 256K),
as it is currently locked by task A;
7) Task A enters btrfs_get_blocks_direct_write() and tries to reserve data
space. Because we are low on available free space, it triggers the
async data reclaim task, and waits for it to reserve data space;
8) The async reclaim task decides to wait for all existing ordered extents
to complete (through btrfs_wait_ordered_roots()).
It finds the ordered extent previously created by task A for the file
range [0, 128K) and waits for it to complete;
9) The ordered extent for the file range [0, 128K) can not complete
because it blocks at btrfs_finish_ordered_io() when trying to lock the
file range [0, 128K).
This results in a deadlock, because:
- task B is holding the file range [0, 128K) locked, waiting for the
range [128K, 256K) to be unlocked by task A;
- task A is holding the file range [128K, 256K) locked and it's waiting
for the async data reclaim task to satisfy its space reservation
request;
- the async data reclaim task is waiting for ordered extent [0, 128K)
to complete, but the ordered extent can not complete because the
file range [0, 128K) is currently locked by task B, which is waiting
on task A to unlock file range [128K, 256K) and task A waiting
on the async data reclaim task.
This results in a deadlock between 4 task: task A, task B, the async
data reclaim task and the task doing ordered extent completion (a work
queue task).
This type of deadlock can sporadically be triggered by the test case
generic/300 from fstests, and results in a stack trace like the following:
[12084.033689] INFO: task kworker/u16:7:123749 blocked for more than 241 seconds.
[12084.034877] Not tainted 5.18.0-rc2-btrfs-next-115 #1
[12084.035562] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[12084.036548] task:kworker/u16:7 state:D stack: 0 pid:123749 ppid: 2 flags:0x00004000
[12084.036554] Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs]
[12084.036599] Call Trace:
[12084.036601] <TASK>
[12084.036606] __schedule+0x3cb/0xed0
[12084.036616] schedule+0x4e/0xb0
[12084.036620] btrfs_start_ordered_extent+0x109/0x1c0 [btrfs]
[12084.036651] ? prepare_to_wait_exclusive+0xc0/0xc0
[12084.036659] btrfs_run_ordered_extent_work+0x1a/0x30 [btrfs]
[12084.036688] btrfs_work_helper+0xf8/0x400 [btrfs]
[12084.0367
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: lpfc: Move cfg_log_verbose check before calling lpfc_dmp_dbg()
In an attempt to log message 0126 with LOG_TRACE_EVENT, the following hard
lockup call trace hangs the system.
Call Trace:
_raw_spin_lock_irqsave+0x32/0x40
lpfc_dmp_dbg.part.32+0x28/0x220 [lpfc]
lpfc_cmpl_els_fdisc+0x145/0x460 [lpfc]
lpfc_sli_cancel_jobs+0x92/0xd0 [lpfc]
lpfc_els_flush_cmd+0x43c/0x670 [lpfc]
lpfc_els_flush_all_cmd+0x37/0x60 [lpfc]
lpfc_sli4_async_event_proc+0x956/0x1720 [lpfc]
lpfc_do_work+0x1485/0x1d70 [lpfc]
kthread+0x112/0x130
ret_from_fork+0x1f/0x40
Kernel panic - not syncing: Hard LOCKUP
The same CPU tries to claim the phba->port_list_lock twice.
Move the cfg_log_verbose checks as part of the lpfc_printf_vlog() and
lpfc_printf_log() macros before calling lpfc_dmp_dbg(). There is no need
to take the phba->port_list_lock within lpfc_dmp_dbg(). |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: lpfc: Fix SCSI I/O completion and abort handler deadlock
During stress I/O tests with 500+ vports, hard LOCKUP call traces are
observed.
CPU A:
native_queued_spin_lock_slowpath+0x192
_raw_spin_lock_irqsave+0x32
lpfc_handle_fcp_err+0x4c6
lpfc_fcp_io_cmd_wqe_cmpl+0x964
lpfc_sli4_fp_handle_cqe+0x266
__lpfc_sli4_process_cq+0x105
__lpfc_sli4_hba_process_cq+0x3c
lpfc_cq_poll_hdler+0x16
irq_poll_softirq+0x76
__softirqentry_text_start+0xe4
irq_exit+0xf7
do_IRQ+0x7f
CPU B:
native_queued_spin_lock_slowpath+0x5b
_raw_spin_lock+0x1c
lpfc_abort_handler+0x13e
scmd_eh_abort_handler+0x85
process_one_work+0x1a7
worker_thread+0x30
kthread+0x112
ret_from_fork+0x1f
Diagram of lockup:
CPUA CPUB
---- ----
lpfc_cmd->buf_lock
phba->hbalock
lpfc_cmd->buf_lock
phba->hbalock
Fix by reordering the taking of the lpfc_cmd->buf_lock and phba->hbalock in
lpfc_abort_handler routine so that it tries to take the lpfc_cmd->buf_lock
first before phba->hbalock. |
| In the Linux kernel, the following vulnerability has been resolved:
loop: implement ->free_disk
Ensure that the lo_device which is stored in the gendisk private
data is valid until the gendisk is freed. Currently the loop driver
uses a lot of effort to make sure a device is not freed when it is
still in use, but to to fix a potential deadlock this will be relaxed
a bit soon. |
| In the Linux kernel, the following vulnerability has been resolved:
media: mediatek: vcodec: prevent kernel crash when rmmod mtk-vcodec-dec.ko
If the driver support subdev mode, the parameter "dev->pm.dev" will be
NULL in mtk_vcodec_dec_remove. Kernel will crash when try to rmmod
mtk-vcodec-dec.ko.
[ 4380.702726] pc : do_raw_spin_trylock+0x4/0x80
[ 4380.707075] lr : _raw_spin_lock_irq+0x90/0x14c
[ 4380.711509] sp : ffff80000819bc10
[ 4380.714811] x29: ffff80000819bc10 x28: ffff3600c03e4000 x27: 0000000000000000
[ 4380.721934] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
[ 4380.729057] x23: ffff3600c0f34930 x22: ffffd5e923549000 x21: 0000000000000220
[ 4380.736179] x20: 0000000000000208 x19: ffffd5e9213e8ebc x18: 0000000000000020
[ 4380.743298] x17: 0000002000000000 x16: ffffd5e9213e8e90 x15: 696c346f65646976
[ 4380.750420] x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000040
[ 4380.757542] x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
[ 4380.764664] x8 : 0000000000000000 x7 : ffff3600c7273ae8 x6 : ffffd5e9213e8ebc
[ 4380.771786] x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
[ 4380.778908] x2 : 0000000000000000 x1 : ffff3600c03e4000 x0 : 0000000000000208
[ 4380.786031] Call trace:
[ 4380.788465] do_raw_spin_trylock+0x4/0x80
[ 4380.792462] __pm_runtime_disable+0x2c/0x1b0
[ 4380.796723] mtk_vcodec_dec_remove+0x5c/0xa0 [mtk_vcodec_dec]
[ 4380.802466] platform_remove+0x2c/0x60
[ 4380.806204] __device_release_driver+0x194/0x250
[ 4380.810810] driver_detach+0xc8/0x15c
[ 4380.814462] bus_remove_driver+0x5c/0xb0
[ 4380.818375] driver_unregister+0x34/0x64
[ 4380.822288] platform_driver_unregister+0x18/0x24
[ 4380.826979] mtk_vcodec_dec_driver_exit+0x1c/0x888 [mtk_vcodec_dec]
[ 4380.833240] __arm64_sys_delete_module+0x190/0x224
[ 4380.838020] invoke_syscall+0x48/0x114
[ 4380.841760] el0_svc_common.constprop.0+0x60/0x11c
[ 4380.846540] do_el0_svc+0x28/0x90
[ 4380.849844] el0_svc+0x4c/0x100
[ 4380.852975] el0t_64_sync_handler+0xec/0xf0
[ 4380.857148] el0t_64_sync+0x190/0x194
[ 4380.860801] Code: 94431515 17ffffca d503201f d503245f (b9400004) |
| In the Linux kernel, the following vulnerability has been resolved:
nvdimm: Fix firmware activation deadlock scenarios
Lockdep reports the following deadlock scenarios for CXL root device
power-management, device_prepare(), operations, and device_shutdown()
operations for 'nd_region' devices:
Chain exists of:
&nvdimm_region_key --> &nvdimm_bus->reconfig_mutex --> system_transition_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(system_transition_mutex);
lock(&nvdimm_bus->reconfig_mutex);
lock(system_transition_mutex);
lock(&nvdimm_region_key);
Chain exists of:
&cxl_nvdimm_bridge_key --> acpi_scan_lock --> &cxl_root_key
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&cxl_root_key);
lock(acpi_scan_lock);
lock(&cxl_root_key);
lock(&cxl_nvdimm_bridge_key);
These stem from holding nvdimm_bus_lock() over hibernate_quiet_exec()
which walks the entire system device topology taking device_lock() along
the way. The nvdimm_bus_lock() is protecting against unregistration,
multiple simultaneous ops callers, and preventing activate_show() from
racing activate_store(). For the first 2, the lock is redundant.
Unregistration already flushes all ops users, and sysfs already prevents
multiple threads to be active in an ops handler at the same time. For
the last userspace should already be waiting for its last
activate_store() to complete, and does not need activate_show() to flush
the write side, so this lock usage can be deleted in these attributes. |
| In the Linux kernel, the following vulnerability has been resolved:
tty: fix deadlock caused by calling printk() under tty_port->lock
pty_write() invokes kmalloc() which may invoke a normal printk() to print
failure message. This can cause a deadlock in the scenario reported by
syz-bot below:
CPU0 CPU1 CPU2
---- ---- ----
lock(console_owner);
lock(&port_lock_key);
lock(&port->lock);
lock(&port_lock_key);
lock(&port->lock);
lock(console_owner);
As commit dbdda842fe96 ("printk: Add console owner and waiter logic to
load balance console writes") said, such deadlock can be prevented by
using printk_deferred() in kmalloc() (which is invoked in the section
guarded by the port->lock). But there are too many printk() on the
kmalloc() path, and kmalloc() can be called from anywhere, so changing
printk() to printk_deferred() is too complicated and inelegant.
Therefore, this patch chooses to specify __GFP_NOWARN to kmalloc(), so
that printk() will not be called, and this deadlock problem can be
avoided.
Syzbot reported the following lockdep error:
======================================================
WARNING: possible circular locking dependency detected
5.4.143-00237-g08ccc19a-dirty #10 Not tainted
------------------------------------------------------
syz-executor.4/29420 is trying to acquire lock:
ffffffff8aedb2a0 (console_owner){....}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:1752 [inline]
ffffffff8aedb2a0 (console_owner){....}-{0:0}, at: vprintk_emit+0x2ca/0x470 kernel/printk/printk.c:2023
but task is already holding lock:
ffff8880119c9158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xf4/0x1f0 drivers/tty/pty.c:120
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&port->lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x35/0x50 kernel/locking/spinlock.c:159
tty_port_tty_get drivers/tty/tty_port.c:288 [inline] <-- lock(&port->lock);
tty_port_default_wakeup+0x1d/0xb0 drivers/tty/tty_port.c:47
serial8250_tx_chars+0x530/0xa80 drivers/tty/serial/8250/8250_port.c:1767
serial8250_handle_irq.part.0+0x31f/0x3d0 drivers/tty/serial/8250/8250_port.c:1854
serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1827 [inline] <-- lock(&port_lock_key);
serial8250_default_handle_irq+0xb2/0x220 drivers/tty/serial/8250/8250_port.c:1870
serial8250_interrupt+0xfd/0x200 drivers/tty/serial/8250/8250_core.c:126
__handle_irq_event_percpu+0x109/0xa50 kernel/irq/handle.c:156
[...]
-> #1 (&port_lock_key){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x35/0x50 kernel/locking/spinlock.c:159
serial8250_console_write+0x184/0xa40 drivers/tty/serial/8250/8250_port.c:3198
<-- lock(&port_lock_key);
call_console_drivers kernel/printk/printk.c:1819 [inline]
console_unlock+0x8cb/0xd00 kernel/printk/printk.c:2504
vprintk_emit+0x1b5/0x470 kernel/printk/printk.c:2024 <-- lock(console_owner);
vprintk_func+0x8d/0x250 kernel/printk/printk_safe.c:394
printk+0xba/0xed kernel/printk/printk.c:2084
register_console+0x8b3/0xc10 kernel/printk/printk.c:2829
univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:681
console_init+0x49d/0x6d3 kernel/printk/printk.c:2915
start_kernel+0x5e9/0x879 init/main.c:713
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
-> #0 (console_owner){....}-{0:0}:
[...]
lock_acquire+0x127/0x340 kernel/locking/lockdep.c:4734
console_trylock_spinning kernel/printk/printk.c:1773
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
block: Fix potential deadlock in blk_ia_range_sysfs_show()
When being read, a sysfs attribute is already protected against removal
with the kobject node active reference counter. As a result, in
blk_ia_range_sysfs_show(), there is no need to take the queue sysfs
lock when reading the value of a range attribute. Using the queue sysfs
lock in this function creates a potential deadlock situation with the
disk removal, something that a lockdep signals with a splat when the
device is removed:
[ 760.703551] Possible unsafe locking scenario:
[ 760.703551]
[ 760.703554] CPU0 CPU1
[ 760.703556] ---- ----
[ 760.703558] lock(&q->sysfs_lock);
[ 760.703565] lock(kn->active#385);
[ 760.703573] lock(&q->sysfs_lock);
[ 760.703579] lock(kn->active#385);
[ 760.703587]
[ 760.703587] *** DEADLOCK ***
Solve this by removing the mutex_lock()/mutex_unlock() calls from
blk_ia_range_sysfs_show(). |
| In the Linux kernel, the following vulnerability has been resolved:
driver core: fix deadlock in __device_attach
In __device_attach function, The lock holding logic is as follows:
...
__device_attach
device_lock(dev) // get lock dev
async_schedule_dev(__device_attach_async_helper, dev); // func
async_schedule_node
async_schedule_node_domain(func)
entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC);
/* when fail or work limit, sync to execute func, but
__device_attach_async_helper will get lock dev as
well, which will lead to A-A deadlock. */
if (!entry || atomic_read(&entry_count) > MAX_WORK) {
func;
else
queue_work_node(node, system_unbound_wq, &entry->work)
device_unlock(dev)
As shown above, when it is allowed to do async probes, because of
out of memory or work limit, async work is not allowed, to do
sync execute instead. it will lead to A-A deadlock because of
__device_attach_async_helper getting lock dev.
To fix the deadlock, move the async_schedule_dev outside device_lock,
as we can see, in async_schedule_node_domain, the parameter of
queue_work_node is system_unbound_wq, so it can accept concurrent
operations. which will also not change the code logic, and will
not lead to deadlock. |
| In the Linux kernel, the following vulnerability has been resolved:
bcache: avoid journal no-space deadlock by reserving 1 journal bucket
The journal no-space deadlock was reported time to time. Such deadlock
can happen in the following situation.
When all journal buckets are fully filled by active jset with heavy
write I/O load, the cache set registration (after a reboot) will load
all active jsets and inserting them into the btree again (which is
called journal replay). If a journaled bkey is inserted into a btree
node and results btree node split, new journal request might be
triggered. For example, the btree grows one more level after the node
split, then the root node record in cache device super block will be
upgrade by bch_journal_meta() from bch_btree_set_root(). But there is no
space in journal buckets, the journal replay has to wait for new journal
bucket to be reclaimed after at least one journal bucket replayed. This
is one example that how the journal no-space deadlock happens.
The solution to avoid the deadlock is to reserve 1 journal bucket in
run time, and only permit the reserved journal bucket to be used during
cache set registration procedure for things like journal replay. Then
the journal space will never be fully filled, there is no chance for
journal no-space deadlock to happen anymore.
This patch adds a new member "bool do_reserve" in struct journal, it is
inititalized to 0 (false) when struct journal is allocated, and set to
1 (true) by bch_journal_space_reserve() when all initialization done in
run_cache_set(). In the run time when journal_reclaim() tries to
allocate a new journal bucket, free_journal_buckets() is called to check
whether there are enough free journal buckets to use. If there is only
1 free journal bucket and journal->do_reserve is 1 (true), the last
bucket is reserved and free_journal_buckets() will return 0 to indicate
no free journal bucket. Then journal_reclaim() will give up, and try
next time to see whetheer there is free journal bucket to allocate. By
this method, there is always 1 jouranl bucket reserved in run time.
During the cache set registration, journal->do_reserve is 0 (false), so
the reserved journal bucket can be used to avoid the no-space deadlock. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix sleeping function called from invalid context on RT kernel
When setting bootparams="trace_event=initcall:initcall_start tp_printk=1" in the
cmdline, the output_printk() was called, and the spin_lock_irqsave() was called in the
atomic and irq disable interrupt context suitation. On the PREEMPT_RT kernel,
these locks are replaced with sleepable rt-spinlock, so the stack calltrace will
be triggered.
Fix it by raw_spin_lock_irqsave when PREEMPT_RT and "trace_event=initcall:initcall_start
tp_printk=1" enabled.
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
preempt_count: 2, expected: 0
RCU nest depth: 0, expected: 0
Preemption disabled at:
[<ffffffff8992303e>] try_to_wake_up+0x7e/0xba0
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.1-rt17+ #19 34c5812404187a875f32bee7977f7367f9679ea7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x60/0x8c
dump_stack+0x10/0x12
__might_resched.cold+0x11d/0x155
rt_spin_lock+0x40/0x70
trace_event_buffer_commit+0x2fa/0x4c0
? map_vsyscall+0x93/0x93
trace_event_raw_event_initcall_start+0xbe/0x110
? perf_trace_initcall_finish+0x210/0x210
? probe_sched_wakeup+0x34/0x40
? ttwu_do_wakeup+0xda/0x310
? trace_hardirqs_on+0x35/0x170
? map_vsyscall+0x93/0x93
do_one_initcall+0x217/0x3c0
? trace_event_raw_event_initcall_level+0x170/0x170
? push_cpu_stop+0x400/0x400
? cblist_init_generic+0x241/0x290
kernel_init_freeable+0x1ac/0x347
? _raw_spin_unlock_irq+0x65/0x80
? rest_init+0xf0/0xf0
kernel_init+0x1e/0x150
ret_from_fork+0x22/0x30
</TASK> |
| In the Linux kernel, the following vulnerability has been resolved:
NFSv4: Don't hold the layoutget locks across multiple RPC calls
When doing layoutget as part of the open() compound, we have to be
careful to release the layout locks before we can call any further RPC
calls, such as setattr(). The reason is that those calls could trigger
a recall, which could deadlock. |
| In the Linux kernel, the following vulnerability has been resolved:
drivers: staging: rtl8192e: Fix deadlock in rtllib_beacons_stop()
There is a deadlock in rtllib_beacons_stop(), which is shown
below:
(Thread 1) | (Thread 2)
| rtllib_send_beacon()
rtllib_beacons_stop() | mod_timer()
spin_lock_irqsave() //(1) | (wait a time)
... | rtllib_send_beacon_cb()
del_timer_sync() | spin_lock_irqsave() //(2)
(wait timer to stop) | ...
We hold ieee->beacon_lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need ieee->beacon_lock in position (2) of thread 2.
As a result, rtllib_beacons_stop() will block forever.
This patch extracts del_timer_sync() from the protection of
spin_lock_irqsave(), which could let timer handler to obtain
the needed lock. |
| In the Linux kernel, the following vulnerability has been resolved:
drivers: usb: host: Fix deadlock in oxu_bus_suspend()
There is a deadlock in oxu_bus_suspend(), which is shown below:
(Thread 1) | (Thread 2)
| timer_action()
oxu_bus_suspend() | mod_timer()
spin_lock_irq() //(1) | (wait a time)
... | oxu_watchdog()
del_timer_sync() | spin_lock_irq() //(2)
(wait timer to stop) | ...
We hold oxu->lock in position (1) of thread 1, and use
del_timer_sync() to wait timer to stop, but timer handler
also need oxu->lock in position (2) of thread 2. As a result,
oxu_bus_suspend() will block forever.
This patch extracts del_timer_sync() from the protection of
spin_lock_irq(), which could let timer handler to obtain
the needed lock. |
| In the Linux kernel, the following vulnerability has been resolved:
drivers: staging: rtl8192bs: Fix deadlock in rtw_joinbss_event_prehandle()
There is a deadlock in rtw_joinbss_event_prehandle(), which is shown
below:
(Thread 1) | (Thread 2)
| _set_timer()
rtw_joinbss_event_prehandle()| mod_timer()
spin_lock_bh() //(1) | (wait a time)
... | _rtw_join_timeout_handler()
del_timer_sync() | spin_lock_bh() //(2)
(wait timer to stop) | ...
We hold pmlmepriv->lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need pmlmepriv->lock in position (2) of thread 2.
As a result, rtw_joinbss_event_prehandle() will block forever.
This patch extracts del_timer_sync() from the protection of
spin_lock_bh(), which could let timer handler to obtain
the needed lock. What`s more, we change spin_lock_bh() to
spin_lock_irq() in _rtw_join_timeout_handler() in order to
prevent deadlock. |
| In the Linux kernel, the following vulnerability has been resolved:
drivers: staging: rtl8192u: Fix deadlock in ieee80211_beacons_stop()
There is a deadlock in ieee80211_beacons_stop(), which is shown below:
(Thread 1) | (Thread 2)
| ieee80211_send_beacon()
ieee80211_beacons_stop() | mod_timer()
spin_lock_irqsave() //(1) | (wait a time)
... | ieee80211_send_beacon_cb()
del_timer_sync() | spin_lock_irqsave() //(2)
(wait timer to stop) | ...
We hold ieee->beacon_lock in position (1) of thread 1 and use
del_timer_sync() to wait timer to stop, but timer handler
also need ieee->beacon_lock in position (2) of thread 2.
As a result, ieee80211_beacons_stop() will block forever.
This patch extracts del_timer_sync() from the protection of
spin_lock_irqsave(), which could let timer handler to obtain
the needed lock. |
| In the Linux kernel, the following vulnerability has been resolved:
drivers: tty: serial: Fix deadlock in sa1100_set_termios()
There is a deadlock in sa1100_set_termios(), which is shown
below:
(Thread 1) | (Thread 2)
| sa1100_enable_ms()
sa1100_set_termios() | mod_timer()
spin_lock_irqsave() //(1) | (wait a time)
... | sa1100_timeout()
del_timer_sync() | spin_lock_irqsave() //(2)
(wait timer to stop) | ...
We hold sport->port.lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need sport->port.lock in position (2) of thread 2. As a result,
sa1100_set_termios() will block forever.
This patch moves del_timer_sync() before spin_lock_irqsave()
in order to prevent the deadlock. |
| In the Linux kernel, the following vulnerability has been resolved:
drivers: staging: rtl8192eu: Fix deadlock in rtw_joinbss_event_prehandle
There is a deadlock in rtw_joinbss_event_prehandle(), which is shown below:
(Thread 1) | (Thread 2)
| _set_timer()
rtw_joinbss_event_prehandle()| mod_timer()
spin_lock_bh() //(1) | (wait a time)
... | rtw_join_timeout_handler()
| _rtw_join_timeout_handler()
del_timer_sync() | spin_lock_bh() //(2)
(wait timer to stop) | ...
We hold pmlmepriv->lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need pmlmepriv->lock in position (2) of thread 2.
As a result, rtw_joinbss_event_prehandle() will block forever.
This patch extracts del_timer_sync() from the protection of
spin_lock_bh(), which could let timer handler to obtain
the needed lock. What`s more, we change spin_lock_bh() to
spin_lock_irq() in _rtw_join_timeout_handler() in order to
prevent deadlock. |
| In the Linux kernel, the following vulnerability has been resolved:
ceph: fix possible deadlock when holding Fwb to get inline_data
1, mount with wsync.
2, create a file with O_RDWR, and the request was sent to mds.0:
ceph_atomic_open()-->
ceph_mdsc_do_request(openc)
finish_open(file, dentry, ceph_open)-->
ceph_open()-->
ceph_init_file()-->
ceph_init_file_info()-->
ceph_uninline_data()-->
{
...
if (inline_version == 1 || /* initial version, no data */
inline_version == CEPH_INLINE_NONE)
goto out_unlock;
...
}
The inline_version will be 1, which is the initial version for the
new create file. And here the ci->i_inline_version will keep with 1,
it's buggy.
3, buffer write to the file immediately:
ceph_write_iter()-->
ceph_get_caps(file, need=Fw, want=Fb, ...);
generic_perform_write()-->
a_ops->write_begin()-->
ceph_write_begin()-->
netfs_write_begin()-->
netfs_begin_read()-->
netfs_rreq_submit_slice()-->
netfs_read_from_server()-->
rreq->netfs_ops->issue_read()-->
ceph_netfs_issue_read()-->
{
...
if (ci->i_inline_version != CEPH_INLINE_NONE &&
ceph_netfs_issue_op_inline(subreq))
return;
...
}
ceph_put_cap_refs(ci, Fwb);
The ceph_netfs_issue_op_inline() will send a getattr(Fsr) request to
mds.1.
4, then the mds.1 will request the rd lock for CInode::filelock from
the auth mds.0, the mds.0 will do the CInode::filelock state transation
from excl --> sync, but it need to revoke the Fxwb caps back from the
clients.
While the kernel client has aleady held the Fwb caps and waiting for
the getattr(Fsr).
It's deadlock!
URL: https://tracker.ceph.com/issues/55377 |
