In the Linux kernel, the following vulnerability has been resolved:
gpio: grgpio: Add NULL check in grgpio_probe
devm_kasprintf() can return a NULL pointer on failure,but this
returned value in grgpio_probe is not checked.
Add NULL check in grgpio_probe, to handle kernel NULL
pointer dereference error.
In the Linux kernel, the following vulnerability has been resolved:
nvme-tcp: fix the memleak while create new ctrl failed
Now while we create new ctrl failed, we have not free the
tagset occupied by admin_q, here try to fix it.
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: free inode when ocfs2_get_init_inode() fails
syzbot is reporting busy inodes after unmount, for commit 9c89fe0af826
("ocfs2: Handle error from dquot_initialize()") forgot to call iput() when
new_inode() succeeded and dquot_initialize() failed.
In the Linux kernel, the following vulnerability has been resolved:
can: dev: can_set_termination(): allow sleeping GPIOs
In commit 6e86a1543c37 ("can: dev: provide optional GPIO based
termination support") GPIO based termination support was added.
For no particular reason that patch uses gpiod_set_value() to set the
GPIO. This leads to the following warning, if the systems uses a
sleeping GPIO, i.e. behind an I2C port expander:
| WARNING: CPU: 0 PID: 379 at /drivers/gpio/gpiolib.c:3496 gpiod_set_value+0x50/0x6c
| CPU: 0 UID: 0 PID: 379 Comm: ip Not tainted 6.11.0-20241016-1 #1 823affae360cc91126e4d316d7a614a8bf86236c
Replace gpiod_set_value() by gpiod_set_value_cansleep() to allow the
use of sleeping GPIOs.
In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Fix use after free on unload
System crash is observed with stack trace warning of use after
free. There are 2 signals to tell dpc_thread to terminate (UNLOADING
flag and kthread_stop).
On setting the UNLOADING flag when dpc_thread happens to run at the time
and sees the flag, this causes dpc_thread to exit and clean up
itself. When kthread_stop is called for final cleanup, this causes use
after free.
Remove UNLOADING signal to terminate dpc_thread. Use the kthread_stop
as the main signal to exit dpc_thread.
[596663.812935] kernel BUG at mm/slub.c:294!
[596663.812950] invalid opcode: 0000 [#1] SMP PTI
[596663.812957] CPU: 13 PID: 1475935 Comm: rmmod Kdump: loaded Tainted: G IOE --------- - - 4.18.0-240.el8.x86_64 #1
[596663.812960] Hardware name: HP ProLiant DL380p Gen8, BIOS P70 08/20/2012
[596663.812974] RIP: 0010:__slab_free+0x17d/0x360
...
[596663.813008] Call Trace:
[596663.813022] ? __dentry_kill+0x121/0x170
[596663.813030] ? _cond_resched+0x15/0x30
[596663.813034] ? _cond_resched+0x15/0x30
[596663.813039] ? wait_for_completion+0x35/0x190
[596663.813048] ? try_to_wake_up+0x63/0x540
[596663.813055] free_task+0x5a/0x60
[596663.813061] kthread_stop+0xf3/0x100
[596663.813103] qla2x00_remove_one+0x284/0x440 [qla2xxx]
In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: core: sysfs: Prevent div by zero
Prevent a division by 0 when monitoring is not enabled.
In the Linux kernel, the following vulnerability has been resolved:
pmdomain: imx: gpcv2: Adjust delay after power up handshake
The udelay(5) is not enough, sometimes below kernel panic
still be triggered:
[ 4.012973] Kernel panic - not syncing: Asynchronous SError Interrupt
[ 4.012976] CPU: 2 UID: 0 PID: 186 Comm: (udev-worker) Not tainted 6.12.0-rc2-0.0.0-devel-00004-g8b1b79e88956 #1
[ 4.012982] Hardware name: Toradex Verdin iMX8M Plus WB on Dahlia Board (DT)
[ 4.012985] Call trace:
[...]
[ 4.013029] arm64_serror_panic+0x64/0x70
[ 4.013034] do_serror+0x3c/0x70
[ 4.013039] el1h_64_error_handler+0x30/0x54
[ 4.013046] el1h_64_error+0x64/0x68
[ 4.013050] clk_imx8mp_audiomix_runtime_resume+0x38/0x48
[ 4.013059] __genpd_runtime_resume+0x30/0x80
[ 4.013066] genpd_runtime_resume+0x114/0x29c
[ 4.013073] __rpm_callback+0x48/0x1e0
[ 4.013079] rpm_callback+0x68/0x80
[ 4.013084] rpm_resume+0x3bc/0x6a0
[ 4.013089] __pm_runtime_resume+0x50/0x9c
[ 4.013095] pm_runtime_get_suppliers+0x60/0x8c
[ 4.013101] __driver_probe_device+0x4c/0x14c
[ 4.013108] driver_probe_device+0x3c/0x120
[ 4.013114] __driver_attach+0xc4/0x200
[ 4.013119] bus_for_each_dev+0x7c/0xe0
[ 4.013125] driver_attach+0x24/0x30
[ 4.013130] bus_add_driver+0x110/0x240
[ 4.013135] driver_register+0x68/0x124
[ 4.013142] __platform_driver_register+0x24/0x30
[ 4.013149] sdma_driver_init+0x20/0x1000 [imx_sdma]
[ 4.013163] do_one_initcall+0x60/0x1e0
[ 4.013168] do_init_module+0x5c/0x21c
[ 4.013175] load_module+0x1a98/0x205c
[ 4.013181] init_module_from_file+0x88/0xd4
[ 4.013187] __arm64_sys_finit_module+0x258/0x350
[ 4.013194] invoke_syscall.constprop.0+0x50/0xe0
[ 4.013202] do_el0_svc+0xa8/0xe0
[ 4.013208] el0_svc+0x3c/0x140
[ 4.013215] el0t_64_sync_handler+0x120/0x12c
[ 4.013222] el0t_64_sync+0x190/0x194
[ 4.013228] SMP: stopping secondary CPUs
The correct way is to wait handshake, but it needs BUS clock of
BLK-CTL be enabled, which is in separate driver. So delay is the
only option here. The udelay(10) is a data got by experiment.
In the Linux kernel, the following vulnerability has been resolved:
cacheinfo: Allocate memory during CPU hotplug if not done from the primary CPU
Commit
5944ce092b97 ("arch_topology: Build cacheinfo from primary CPU")
adds functionality that architectures can use to optionally allocate and
build cacheinfo early during boot. Commit
6539cffa9495 ("cacheinfo: Add arch specific early level initializer")
lets secondary CPUs correct (and reallocate memory) cacheinfo data if
needed.
If the early build functionality is not used and cacheinfo does not need
correction, memory for cacheinfo is never allocated. x86 does not use
the early build functionality. Consequently, during the cacheinfo CPU
hotplug callback, last_level_cache_is_valid() attempts to dereference
a NULL pointer:
BUG: kernel NULL pointer dereference, address: 0000000000000100
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEPMT SMP NOPTI
CPU: 0 PID 19 Comm: cpuhp/0 Not tainted 6.4.0-rc2 #1
RIP: 0010: last_level_cache_is_valid+0x95/0xe0a
Allocate memory for cacheinfo during the cacheinfo CPU hotplug callback
if not done earlier.
Moreover, before determining the validity of the last-level cache info,
ensure that it has been allocated. Simply checking for non-zero
cache_leaves() is not sufficient, as some architectures (e.g., Intel
processors) have non-zero cache_leaves() before allocation.
Dereferencing NULL cacheinfo can occur in update_per_cpu_data_slice_size().
This function iterates over all online CPUs. However, a CPU may have come
online recently, but its cacheinfo may not have been allocated yet.
While here, remove an unnecessary indentation in allocate_cache_info().
[ bp: Massage. ]
In the Linux kernel, the following vulnerability has been resolved:
sched/numa: fix memory leak due to the overwritten vma->numab_state
[Problem Description]
When running the hackbench program of LTP, the following memory leak is
reported by kmemleak.
# /opt/ltp/testcases/bin/hackbench 20 thread 1000
Running with 20*40 (== 800) tasks.
# dmesg | grep kmemleak
...
kmemleak: 480 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
kmemleak: 665 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff888cd8ca2c40 (size 64):
comm "hackbench", pid 17142, jiffies 4299780315
hex dump (first 32 bytes):
ac 74 49 00 01 00 00 00 4c 84 49 00 01 00 00 00 .tI.....L.I.....
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc bff18fd4):
[<ffffffff81419a89>] __kmalloc_cache_noprof+0x2f9/0x3f0
[<ffffffff8113f715>] task_numa_work+0x725/0xa00
[<ffffffff8110f878>] task_work_run+0x58/0x90
[<ffffffff81ddd9f8>] syscall_exit_to_user_mode+0x1c8/0x1e0
[<ffffffff81dd78d5>] do_syscall_64+0x85/0x150
[<ffffffff81e0012b>] entry_SYSCALL_64_after_hwframe+0x76/0x7e
...
This issue can be consistently reproduced on three different servers:
* a 448-core server
* a 256-core server
* a 192-core server
[Root Cause]
Since multiple threads are created by the hackbench program (along with
the command argument 'thread'), a shared vma might be accessed by two or
more cores simultaneously. When two or more cores observe that
vma->numab_state is NULL at the same time, vma->numab_state will be
overwritten.
Although current code ensures that only one thread scans the VMAs in a
single 'numa_scan_period', there might be a chance for another thread
to enter in the next 'numa_scan_period' while we have not gotten till
numab_state allocation [1].
Note that the command `/opt/ltp/testcases/bin/hackbench 50 process 1000`
cannot the reproduce the issue. It is verified with 200+ test runs.
[Solution]
Use the cmpxchg atomic operation to ensure that only one thread executes
the vma->numab_state assignment.
[1] https://lore.kernel.org/lkml/1794be3c-358c-4cdc-a43d-a1f841d91ef7@amd.com/
In the Linux kernel, the following vulnerability has been resolved:
mm/gup: handle NULL pages in unpin_user_pages()
The recent addition of "pofs" (pages or folios) handling to gup has a
flaw: it assumes that unpin_user_pages() handles NULL pages in the pages**
array. That's not the case, as I discovered when I ran on a new
configuration on my test machine.
Fix this by skipping NULL pages in unpin_user_pages(), just like
unpin_folios() already does.
Details: when booting on x86 with "numa=fake=2 movablecore=4G" on Linux
6.12, and running this:
tools/testing/selftests/mm/gup_longterm
...I get the following crash:
BUG: kernel NULL pointer dereference, address: 0000000000000008
RIP: 0010:sanity_check_pinned_pages+0x3a/0x2d0
...
Call Trace:
<TASK>
? __die_body+0x66/0xb0
? page_fault_oops+0x30c/0x3b0
? do_user_addr_fault+0x6c3/0x720
? irqentry_enter+0x34/0x60
? exc_page_fault+0x68/0x100
? asm_exc_page_fault+0x22/0x30
? sanity_check_pinned_pages+0x3a/0x2d0
unpin_user_pages+0x24/0xe0
check_and_migrate_movable_pages_or_folios+0x455/0x4b0
__gup_longterm_locked+0x3bf/0x820
? mmap_read_lock_killable+0x12/0x50
? __pfx_mmap_read_lock_killable+0x10/0x10
pin_user_pages+0x66/0xa0
gup_test_ioctl+0x358/0xb20
__se_sys_ioctl+0x6b/0xc0
do_syscall_64+0x7b/0x150
entry_SYSCALL_64_after_hwframe+0x76/0x7e
In the Linux kernel, the following vulnerability has been resolved:
mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM
We currently assume that there is at least one VMA in a MM, which isn't
true.
So we might end up having find_vma() return NULL, to then de-reference
NULL. So properly handle find_vma() returning NULL.
This fixes the report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 6021 Comm: syz-executor284 Not tainted 6.12.0-rc7-syzkaller-00187-gf868cd251776 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
RIP: 0010:migrate_to_node mm/mempolicy.c:1090 [inline]
RIP: 0010:do_migrate_pages+0x403/0x6f0 mm/mempolicy.c:1194
Code: ...
RSP: 0018:ffffc9000375fd08 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffc9000375fd78 RCX: 0000000000000000
RDX: ffff88807e171300 RSI: dffffc0000000000 RDI: ffff88803390c044
RBP: ffff88807e171428 R08: 0000000000000014 R09: fffffbfff2039ef1
R10: ffffffff901cf78f R11: 0000000000000000 R12: 0000000000000003
R13: ffffc9000375fe90 R14: ffffc9000375fe98 R15: ffffc9000375fdf8
FS: 00005555919e1380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555919e1ca8 CR3: 000000007f12a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
kernel_migrate_pages+0x5b2/0x750 mm/mempolicy.c:1709
__do_sys_migrate_pages mm/mempolicy.c:1727 [inline]
__se_sys_migrate_pages mm/mempolicy.c:1723 [inline]
__x64_sys_migrate_pages+0x96/0x100 mm/mempolicy.c:1723
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
[akpm@linux-foundation.org: add unlikely()]
In the Linux kernel, the following vulnerability has been resolved:
kcsan: Turn report_filterlist_lock into a raw_spinlock
Ran Xiaokai reports that with a KCSAN-enabled PREEMPT_RT kernel, we can see
splats like:
| BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
| in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1
| preempt_count: 10002, expected: 0
| RCU nest depth: 0, expected: 0
| no locks held by swapper/1/0.
| irq event stamp: 156674
| hardirqs last enabled at (156673): [<ffffffff81130bd9>] do_idle+0x1f9/0x240
| hardirqs last disabled at (156674): [<ffffffff82254f84>] sysvec_apic_timer_interrupt+0x14/0xc0
| softirqs last enabled at (0): [<ffffffff81099f47>] copy_process+0xfc7/0x4b60
| softirqs last disabled at (0): [<0000000000000000>] 0x0
| Preemption disabled at:
| [<ffffffff814a3e2a>] paint_ptr+0x2a/0x90
| CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.11.0+ #3
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
| Call Trace:
| <IRQ>
| dump_stack_lvl+0x7e/0xc0
| dump_stack+0x1d/0x30
| __might_resched+0x1a2/0x270
| rt_spin_lock+0x68/0x170
| kcsan_skip_report_debugfs+0x43/0xe0
| print_report+0xb5/0x590
| kcsan_report_known_origin+0x1b1/0x1d0
| kcsan_setup_watchpoint+0x348/0x650
| __tsan_unaligned_write1+0x16d/0x1d0
| hrtimer_interrupt+0x3d6/0x430
| __sysvec_apic_timer_interrupt+0xe8/0x3a0
| sysvec_apic_timer_interrupt+0x97/0xc0
| </IRQ>
On a detected data race, KCSAN's reporting logic checks if it should
filter the report. That list is protected by the report_filterlist_lock
*non-raw* spinlock which may sleep on RT kernels.
Since KCSAN may report data races in any context, convert it to a
raw_spinlock.
This requires being careful about when to allocate memory for the filter
list itself which can be done via KCSAN's debugfs interface. Concurrent
modification of the filter list via debugfs should be rare: the chosen
strategy is to optimistically pre-allocate memory before the critical
section and discard if unused.
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath10k: avoid NULL pointer error during sdio remove
When running 'rmmod ath10k', ath10k_sdio_remove() will free sdio
workqueue by destroy_workqueue(). But if CONFIG_INIT_ON_FREE_DEFAULT_ON
is set to yes, kernel panic will happen:
Call trace:
destroy_workqueue+0x1c/0x258
ath10k_sdio_remove+0x84/0x94
sdio_bus_remove+0x50/0x16c
device_release_driver_internal+0x188/0x25c
device_driver_detach+0x20/0x2c
This is because during 'rmmod ath10k', ath10k_sdio_remove() will call
ath10k_core_destroy() before destroy_workqueue(). wiphy_dev_release()
will finally be called in ath10k_core_destroy(). This function will free
struct cfg80211_registered_device *rdev and all its members, including
wiphy, dev and the pointer of sdio workqueue. Then the pointer of sdio
workqueue will be set to NULL due to CONFIG_INIT_ON_FREE_DEFAULT_ON.
After device release, destroy_workqueue() will use NULL pointer then the
kernel panic happen.
Call trace:
ath10k_sdio_remove
->ath10k_core_unregister
……
->ath10k_core_stop
->ath10k_hif_stop
->ath10k_sdio_irq_disable
->ath10k_hif_power_down
->del_timer_sync(&ar_sdio->sleep_timer)
->ath10k_core_destroy
->ath10k_mac_destroy
->ieee80211_free_hw
->wiphy_free
……
->wiphy_dev_release
->destroy_workqueue
Need to call destroy_workqueue() before ath10k_core_destroy(), free
the work queue buffer first and then free pointer of work queue by
ath10k_core_destroy(). This order matches the error path order in
ath10k_sdio_probe().
No work will be queued on sdio workqueue between it is destroyed and
ath10k_core_destroy() is called. Based on the call_stack above, the
reason is:
Only ath10k_sdio_sleep_timer_handler(), ath10k_sdio_hif_tx_sg() and
ath10k_sdio_irq_disable() will queue work on sdio workqueue.
Sleep timer will be deleted before ath10k_core_destroy() in
ath10k_hif_power_down().
ath10k_sdio_irq_disable() only be called in ath10k_hif_stop().
ath10k_core_unregister() will call ath10k_hif_power_down() to stop hif
bus, so ath10k_sdio_hif_tx_sg() won't be called anymore.
Tested-on: QCA6174 hw3.2 SDIO WLAN.RMH.4.4.1-00189
In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: Fix oops due to NULL pointer dereference in brcmf_sdiod_sglist_rw()
This patch fixes a NULL pointer dereference bug in brcmfmac that occurs
when a high 'sd_sgentry_align' value applies (e.g. 512) and a lot of queued SKBs
are sent from the pkt queue.
The problem is the number of entries in the pre-allocated sgtable, it is
nents = max(rxglom_size, txglom_size) + max(rxglom_size, txglom_size) >> 4 + 1.
Given the default [rt]xglom_size=32 it's actually 35 which is too small.
Worst case, the pkt queue can end up with 64 SKBs. This occurs when a new SKB
is added for each original SKB if tailroom isn't enough to hold tail_pad.
At least one sg entry is needed for each SKB. So, eventually the "skb_queue_walk loop"
in brcmf_sdiod_sglist_rw may run out of sg entries. This makes sg_next return
NULL and this causes the oops.
The patch sets nents to max(rxglom_size, txglom_size) * 2 to be able handle
the worst-case.
Btw. this requires only 64-35=29 * 16 (or 20 if CONFIG_NEED_SG_DMA_LENGTH) = 464
additional bytes of memory.
In the Linux kernel, the following vulnerability has been resolved:
bpf: Call free_htab_elem() after htab_unlock_bucket()
For htab of maps, when the map is removed from the htab, it may hold the
last reference of the map. bpf_map_fd_put_ptr() will invoke
bpf_map_free_id() to free the id of the removed map element. However,
bpf_map_fd_put_ptr() is invoked while holding a bucket lock
(raw_spin_lock_t), and bpf_map_free_id() attempts to acquire map_idr_lock
(spinlock_t), triggering the following lockdep warning:
=============================
[ BUG: Invalid wait context ]
6.11.0-rc4+ #49 Not tainted
-----------------------------
test_maps/4881 is trying to lock:
ffffffff84884578 (map_idr_lock){+...}-{3:3}, at: bpf_map_free_id.part.0+0x21/0x70
other info that might help us debug this:
context-{5:5}
2 locks held by test_maps/4881:
#0: ffffffff846caf60 (rcu_read_lock){....}-{1:3}, at: bpf_fd_htab_map_update_elem+0xf9/0x270
#1: ffff888149ced148 (&htab->lockdep_key#2){....}-{2:2}, at: htab_map_update_elem+0x178/0xa80
stack backtrace:
CPU: 0 UID: 0 PID: 4881 Comm: test_maps Not tainted 6.11.0-rc4+ #49
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ...
Call Trace:
<TASK>
dump_stack_lvl+0x6e/0xb0
dump_stack+0x10/0x20
__lock_acquire+0x73e/0x36c0
lock_acquire+0x182/0x450
_raw_spin_lock_irqsave+0x43/0x70
bpf_map_free_id.part.0+0x21/0x70
bpf_map_put+0xcf/0x110
bpf_map_fd_put_ptr+0x9a/0xb0
free_htab_elem+0x69/0xe0
htab_map_update_elem+0x50f/0xa80
bpf_fd_htab_map_update_elem+0x131/0x270
htab_map_update_elem+0x50f/0xa80
bpf_fd_htab_map_update_elem+0x131/0x270
bpf_map_update_value+0x266/0x380
__sys_bpf+0x21bb/0x36b0
__x64_sys_bpf+0x45/0x60
x64_sys_call+0x1b2a/0x20d0
do_syscall_64+0x5d/0x100
entry_SYSCALL_64_after_hwframe+0x76/0x7e
One way to fix the lockdep warning is using raw_spinlock_t for
map_idr_lock as well. However, bpf_map_alloc_id() invokes
idr_alloc_cyclic() after acquiring map_idr_lock, it will trigger a
similar lockdep warning because the slab's lock (s->cpu_slab->lock) is
still a spinlock.
Instead of changing map_idr_lock's type, fix the issue by invoking
htab_put_fd_value() after htab_unlock_bucket(). However, only deferring
the invocation of htab_put_fd_value() is not enough, because the old map
pointers in htab of maps can not be saved during batched deletion.
Therefore, also defer the invocation of free_htab_elem(), so these
to-be-freed elements could be linked together similar to lru map.
There are four callers for ->map_fd_put_ptr:
(1) alloc_htab_elem() (through htab_put_fd_value())
It invokes ->map_fd_put_ptr() under a raw_spinlock_t. The invocation of
htab_put_fd_value() can not simply move after htab_unlock_bucket(),
because the old element has already been stashed in htab->extra_elems.
It may be reused immediately after htab_unlock_bucket() and the
invocation of htab_put_fd_value() after htab_unlock_bucket() may release
the newly-added element incorrectly. Therefore, saving the map pointer
of the old element for htab of maps before unlocking the bucket and
releasing the map_ptr after unlock. Beside the map pointer in the old
element, should do the same thing for the special fields in the old
element as well.
(2) free_htab_elem() (through htab_put_fd_value())
Its caller includes __htab_map_lookup_and_delete_elem(),
htab_map_delete_elem() and __htab_map_lookup_and_delete_batch().
For htab_map_delete_elem(), simply invoke free_htab_elem() after
htab_unlock_bucket(). For __htab_map_lookup_and_delete_batch(), just
like lru map, linking the to-be-freed element into node_to_free list
and invoking free_htab_elem() for these element after unlock. It is safe
to reuse batch_flink as the link for node_to_free, because these
elements have been removed from the hash llist.
Because htab of maps doesn't support lookup_and_delete operation,
__htab_map_lookup_and_delete_elem() doesn't have the problem, so kept
it as
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_conn: Use disable_delayed_work_sync
This makes use of disable_delayed_work_sync instead
cancel_delayed_work_sync as it not only cancel the ongoing work but also
disables new submit which is disarable since the object holding the work
is about to be freed.
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_core: Fix not checking skb length on hci_acldata_packet
This fixes not checking if skb really contains an ACL header otherwise
the code may attempt to access some uninitilized/invalid memory past the
valid skb->data.
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix f2fs_bug_on when uninstalling filesystem call f2fs_evict_inode.
creating a large files during checkpoint disable until it runs out of
space and then delete it, then remount to enable checkpoint again, and
then unmount the filesystem triggers the f2fs_bug_on as below:
------------[ cut here ]------------
kernel BUG at fs/f2fs/inode.c:896!
CPU: 2 UID: 0 PID: 1286 Comm: umount Not tainted 6.11.0-rc7-dirty #360
Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
RIP: 0010:f2fs_evict_inode+0x58c/0x610
Call Trace:
__die_body+0x15/0x60
die+0x33/0x50
do_trap+0x10a/0x120
f2fs_evict_inode+0x58c/0x610
do_error_trap+0x60/0x80
f2fs_evict_inode+0x58c/0x610
exc_invalid_op+0x53/0x60
f2fs_evict_inode+0x58c/0x610
asm_exc_invalid_op+0x16/0x20
f2fs_evict_inode+0x58c/0x610
evict+0x101/0x260
dispose_list+0x30/0x50
evict_inodes+0x140/0x190
generic_shutdown_super+0x2f/0x150
kill_block_super+0x11/0x40
kill_f2fs_super+0x7d/0x140
deactivate_locked_super+0x2a/0x70
cleanup_mnt+0xb3/0x140
task_work_run+0x61/0x90
The root cause is: creating large files during disable checkpoint
period results in not enough free segments, so when writing back root
inode will failed in f2fs_enable_checkpoint. When umount the file
system after enabling checkpoint, the root inode is dirty in
f2fs_evict_inode function, which triggers BUG_ON. The steps to
reproduce are as follows:
dd if=/dev/zero of=f2fs.img bs=1M count=55
mount f2fs.img f2fs_dir -o checkpoint=disable:10%
dd if=/dev/zero of=big bs=1M count=50
sync
rm big
mount -o remount,checkpoint=enable f2fs_dir
umount f2fs_dir
Let's redirty inode when there is not free segments during checkpoint
is disable.
In the Linux kernel, the following vulnerability has been resolved:
io_uring/tctx: work around xa_store() allocation error issue
syzbot triggered the following WARN_ON:
WARNING: CPU: 0 PID: 16 at io_uring/tctx.c:51 __io_uring_free+0xfa/0x140 io_uring/tctx.c:51
which is the
WARN_ON_ONCE(!xa_empty(&tctx->xa));
sanity check in __io_uring_free() when a io_uring_task is going through
its final put. The syzbot test case includes injecting memory allocation
failures, and it very much looks like xa_store() can fail one of its
memory allocations and end up with ->head being non-NULL even though no
entries exist in the xarray.
Until this issue gets sorted out, work around it by attempting to
iterate entries in our xarray, and WARN_ON_ONCE() if one is found.
In the Linux kernel, the following vulnerability has been resolved:
sched/deadline: Fix warning in migrate_enable for boosted tasks
When running the following command:
while true; do
stress-ng --cyclic 30 --timeout 30s --minimize --quiet
done
a warning is eventually triggered:
WARNING: CPU: 43 PID: 2848 at kernel/sched/deadline.c:794
setup_new_dl_entity+0x13e/0x180
...
Call Trace:
<TASK>
? show_trace_log_lvl+0x1c4/0x2df
? enqueue_dl_entity+0x631/0x6e0
? setup_new_dl_entity+0x13e/0x180
? __warn+0x7e/0xd0
? report_bug+0x11a/0x1a0
? handle_bug+0x3c/0x70
? exc_invalid_op+0x14/0x70
? asm_exc_invalid_op+0x16/0x20
enqueue_dl_entity+0x631/0x6e0
enqueue_task_dl+0x7d/0x120
__do_set_cpus_allowed+0xe3/0x280
__set_cpus_allowed_ptr_locked+0x140/0x1d0
__set_cpus_allowed_ptr+0x54/0xa0
migrate_enable+0x7e/0x150
rt_spin_unlock+0x1c/0x90
group_send_sig_info+0xf7/0x1a0
? kill_pid_info+0x1f/0x1d0
kill_pid_info+0x78/0x1d0
kill_proc_info+0x5b/0x110
__x64_sys_kill+0x93/0xc0
do_syscall_64+0x5c/0xf0
entry_SYSCALL_64_after_hwframe+0x6e/0x76
RIP: 0033:0x7f0dab31f92b
This warning occurs because set_cpus_allowed dequeues and enqueues tasks
with the ENQUEUE_RESTORE flag set. If the task is boosted, the warning
is triggered. A boosted task already had its parameters set by
rt_mutex_setprio, and a new call to setup_new_dl_entity is unnecessary,
hence the WARN_ON call.
Check if we are requeueing a boosted task and avoid calling
setup_new_dl_entity if that's the case.
In the Linux kernel, the following vulnerability has been resolved:
media: qcom: camss: fix error path on configuration of power domains
There is a chance to meet runtime issues during configuration of CAMSS
power domains, because on the error path dev_pm_domain_detach() is
unexpectedly called with NULL or error pointer.
One of the simplest ways to reproduce the problem is to probe CAMSS
driver before registration of CAMSS power domains, for instance if
a platform CAMCC driver is simply not built.
Warning backtrace example:
Unable to handle kernel NULL pointer dereference at virtual address 00000000000001a2
<snip>
pc : dev_pm_domain_detach+0x8/0x48
lr : camss_probe+0x374/0x9c0
<snip>
Call trace:
dev_pm_domain_detach+0x8/0x48
platform_probe+0x70/0xf0
really_probe+0xc4/0x2a8
__driver_probe_device+0x80/0x140
driver_probe_device+0x48/0x170
__device_attach_driver+0xc0/0x148
bus_for_each_drv+0x88/0xf0
__device_attach+0xb0/0x1c0
device_initial_probe+0x1c/0x30
bus_probe_device+0xb4/0xc0
deferred_probe_work_func+0x90/0xd0
process_one_work+0x164/0x3e0
worker_thread+0x310/0x420
kthread+0x120/0x130
ret_from_fork+0x10/0x20
In the Linux kernel, the following vulnerability has been resolved:
media: amphion: Set video drvdata before register video device
The video drvdata should be set before the video device is registered,
otherwise video_drvdata() may return NULL in the open() file ops, and led
to oops.
In the Linux kernel, the following vulnerability has been resolved:
media: imx-jpeg: Set video drvdata before register video device
The video drvdata should be set before the video device is registered,
otherwise video_drvdata() may return NULL in the open() file ops, and led
to oops.
In the Linux kernel, the following vulnerability has been resolved:
media: ts2020: fix null-ptr-deref in ts2020_probe()
KASAN reported a null-ptr-deref issue when executing the following
command:
# echo ts2020 0x20 > /sys/bus/i2c/devices/i2c-0/new_device
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 53 UID: 0 PID: 970 Comm: systemd-udevd Not tainted 6.12.0-rc2+ #24
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)
RIP: 0010:ts2020_probe+0xad/0xe10 [ts2020]
RSP: 0018:ffffc9000abbf598 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffffc0714809
RDX: 0000000000000002 RSI: ffff88811550be00 RDI: 0000000000000010
RBP: ffff888109868800 R08: 0000000000000001 R09: fffff52001577eb6
R10: 0000000000000000 R11: ffffc9000abbff50 R12: ffffffffc0714790
R13: 1ffff92001577eb8 R14: ffffffffc07190d0 R15: 0000000000000001
FS: 00007f95f13b98c0(0000) GS:ffff888149280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555d2634b000 CR3: 0000000152236000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ts2020_probe+0xad/0xe10 [ts2020]
i2c_device_probe+0x421/0xb40
really_probe+0x266/0x850
...
The cause of the problem is that when using sysfs to dynamically register
an i2c device, there is no platform data, but the probe process of ts2020
needs to use platform data, resulting in a null pointer being accessed.
Solve this problem by adding checks to platform data.
In the Linux kernel, the following vulnerability has been resolved:
efi/libstub: Free correct pointer on failure
cmdline_ptr is an out parameter, which is not allocated by the function
itself, and likely points into the caller's stack.
cmdline refers to the pool allocation that should be freed when cleaning
up after a failure, so pass this instead to free_pool().
In the Linux kernel, the following vulnerability has been resolved:
media: platform: allegro-dvt: Fix possible memory leak in allocate_buffers_internal()
The buffer in the loop should be released under the exception path,
otherwise there may be a memory leak here.
To mitigate this, free the buffer when allegro_alloc_buffer fails.
In the Linux kernel, the following vulnerability has been resolved:
ftrace: Fix regression with module command in stack_trace_filter
When executing the following command:
# echo "write*:mod:ext3" > /sys/kernel/tracing/stack_trace_filter
The current mod command causes a null pointer dereference. While commit
0f17976568b3f ("ftrace: Fix regression with module command in stack_trace_filter")
has addressed part of the issue, it left a corner case unhandled, which still
results in a kernel crash.
In the Linux kernel, the following vulnerability has been resolved:
iommu/arm-smmu: Defer probe of clients after smmu device bound
Null pointer dereference occurs due to a race between smmu
driver probe and client driver probe, when of_dma_configure()
for client is called after the iommu_device_register() for smmu driver
probe has executed but before the driver_bound() for smmu driver
has been called.
Following is how the race occurs:
T1:Smmu device probe T2: Client device probe
really_probe()
arm_smmu_device_probe()
iommu_device_register()
really_probe()
platform_dma_configure()
of_dma_configure()
of_dma_configure_id()
of_iommu_configure()
iommu_probe_device()
iommu_init_device()
arm_smmu_probe_device()
arm_smmu_get_by_fwnode()
driver_find_device_by_fwnode()
driver_find_device()
next_device()
klist_next()
/* null ptr
assigned to smmu */
/* null ptr dereference
while smmu->streamid_mask */
driver_bound()
klist_add_tail()
When this null smmu pointer is dereferenced later in
arm_smmu_probe_device, the device crashes.
Fix this by deferring the probe of the client device
until the smmu device has bound to the arm smmu driver.
[will: Add comment]
In the Linux kernel, the following vulnerability has been resolved:
ad7780: fix division by zero in ad7780_write_raw()
In the ad7780_write_raw() , val2 can be zero, which might lead to a
division by zero error in DIV_ROUND_CLOSEST(). The ad7780_write_raw()
is based on iio_info's write_raw. While val is explicitly declared that
can be zero (in read mode), val2 is not specified to be non-zero.
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to drop all discards after creating snapshot on lvm device
Piergiorgio reported a bug in bugzilla as below:
------------[ cut here ]------------
WARNING: CPU: 2 PID: 969 at fs/f2fs/segment.c:1330
RIP: 0010:__submit_discard_cmd+0x27d/0x400 [f2fs]
Call Trace:
__issue_discard_cmd+0x1ca/0x350 [f2fs]
issue_discard_thread+0x191/0x480 [f2fs]
kthread+0xcf/0x100
ret_from_fork+0x31/0x50
ret_from_fork_asm+0x1a/0x30
w/ below testcase, it can reproduce this bug quickly:
- pvcreate /dev/vdb
- vgcreate myvg1 /dev/vdb
- lvcreate -L 1024m -n mylv1 myvg1
- mount /dev/myvg1/mylv1 /mnt/f2fs
- dd if=/dev/zero of=/mnt/f2fs/file bs=1M count=20
- sync
- rm /mnt/f2fs/file
- sync
- lvcreate -L 1024m -s -n mylv1-snapshot /dev/myvg1/mylv1
- umount /mnt/f2fs
The root cause is: it will update discard_max_bytes of mounted lvm
device to zero after creating snapshot on this lvm device, then,
__submit_discard_cmd() will pass parameter @nr_sects w/ zero value
to __blkdev_issue_discard(), it returns a NULL bio pointer, result
in panic.
This patch changes as below for fixing:
1. Let's drop all remained discards in f2fs_unfreeze() if snapshot
of lvm device is created.
2. Checking discard_max_bytes before submitting discard during
__submit_discard_cmd().
In the Linux kernel, the following vulnerability has been resolved:
ceph: pass cred pointer to ceph_mds_auth_match()
This eliminates a redundant get_current_cred() call, because
ceph_mds_check_access() has already obtained this pointer.
As a side effect, this also fixes a reference leak in
ceph_mds_auth_match(): by omitting the get_current_cred() call, no
additional cred reference is taken.
In the Linux kernel, the following vulnerability has been resolved:
i3c: master: Fix miss free init_dyn_addr at i3c_master_put_i3c_addrs()
if (dev->boardinfo && dev->boardinfo->init_dyn_addr)
^^^ here check "init_dyn_addr"
i3c_bus_set_addr_slot_status(&master->bus, dev->info.dyn_addr, ...)
^^^^
free "dyn_addr"
Fix copy/paste error "dyn_addr" by replacing it with "init_dyn_addr".
In the Linux kernel, the following vulnerability has been resolved:
slab: Fix too strict alignment check in create_cache()
On m68k, where the minimum alignment of unsigned long is 2 bytes:
Kernel panic - not syncing: __kmem_cache_create_args: Failed to create slab 'io_kiocb'. Error -22
CPU: 0 UID: 0 PID: 1 Comm: swapper Not tainted 6.12.0-atari-03776-g7eaa1f99261a #1783
Stack from 0102fe5c:
0102fe5c 00514a2b 00514a2b ffffff00 00000001 0051f5ed 00425e78 00514a2b
0041eb74 ffffffea 00000310 0051f5ed ffffffea ffffffea 00601f60 00000044
0102ff20 000e7a68 0051ab8e 004383b8 0051f5ed ffffffea 000000b8 00000007
01020c00 00000000 000e77f0 0041e5f0 005f67c0 0051f5ed 000000b6 0102fef4
00000310 0102fef4 00000000 00000016 005f676c 0060a34c 00000010 00000004
00000038 0000009a 01000000 000000b8 005f668e 0102e000 00001372 0102ff88
Call Trace: [<00425e78>] dump_stack+0xc/0x10
[<0041eb74>] panic+0xd8/0x26c
[<000e7a68>] __kmem_cache_create_args+0x278/0x2e8
[<000e77f0>] __kmem_cache_create_args+0x0/0x2e8
[<0041e5f0>] memset+0x0/0x8c
[<005f67c0>] io_uring_init+0x54/0xd2
The minimal alignment of an integral type may differ from its size,
hence is not safe to assume that an arbitrary freeptr_t (which is
basically an unsigned long) is always aligned to 4 or 8 bytes.
As nothing seems to require the additional alignment, it is safe to fix
this by relaxing the check to the actual minimum alignment of freeptr_t.
In the Linux kernel, the following vulnerability has been resolved:
iio: adc: ad7923: Fix buffer overflow for tx_buf and ring_xfer
The AD7923 was updated to support devices with 8 channels, but the size
of tx_buf and ring_xfer was not increased accordingly, leading to a
potential buffer overflow in ad7923_update_scan_mode().
In the Linux kernel, the following vulnerability has been resolved:
s390/stacktrace: Use break instead of return statement
arch_stack_walk_user_common() contains a return statement instead of a
break statement in case store_ip() fails while trying to store a callchain
entry of a user space process.
This may lead to a missing pagefault_enable() call.
If this happens any subsequent page fault of the process won't be resolved
by the page fault handler and this in turn will lead to the process being
killed.
Use a break instead of a return statement to fix this.
In the Linux kernel, the following vulnerability has been resolved:
cachefiles: Fix NULL pointer dereference in object->file
At present, the object->file has the NULL pointer dereference problem in
ondemand-mode. The root cause is that the allocated fd and object->file
lifetime are inconsistent, and the user-space invocation to anon_fd uses
object->file. Following is the process that triggers the issue:
[write fd] [umount]
cachefiles_ondemand_fd_write_iter
fscache_cookie_state_machine
cachefiles_withdraw_cookie
if (!file) return -ENOBUFS
cachefiles_clean_up_object
cachefiles_unmark_inode_in_use
fput(object->file)
object->file = NULL
// file NULL pointer dereference!
__cachefiles_write(..., file, ...)
Fix this issue by add an additional reference count to the object->file
before write/llseek, and decrement after it finished.
In the Linux kernel, the following vulnerability has been resolved:
rcu/nocb: Fix missed RCU barrier on deoffloading
Currently, running rcutorture test with torture_type=rcu fwd_progress=8
n_barrier_cbs=8 nocbs_nthreads=8 nocbs_toggle=100 onoff_interval=60
test_boost=2, will trigger the following warning:
WARNING: CPU: 19 PID: 100 at kernel/rcu/tree_nocb.h:1061 rcu_nocb_rdp_deoffload+0x292/0x2a0
RIP: 0010:rcu_nocb_rdp_deoffload+0x292/0x2a0
Call Trace:
<TASK>
? __warn+0x7e/0x120
? rcu_nocb_rdp_deoffload+0x292/0x2a0
? report_bug+0x18e/0x1a0
? handle_bug+0x3d/0x70
? exc_invalid_op+0x18/0x70
? asm_exc_invalid_op+0x1a/0x20
? rcu_nocb_rdp_deoffload+0x292/0x2a0
rcu_nocb_cpu_deoffload+0x70/0xa0
rcu_nocb_toggle+0x136/0x1c0
? __pfx_rcu_nocb_toggle+0x10/0x10
kthread+0xd1/0x100
? __pfx_kthread+0x10/0x10
ret_from_fork+0x2f/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
CPU0 CPU2 CPU3
//rcu_nocb_toggle //nocb_cb_wait //rcutorture
// deoffload CPU1 // process CPU1's rdp
rcu_barrier()
rcu_segcblist_entrain()
rcu_segcblist_add_len(1);
// len == 2
// enqueue barrier
// callback to CPU1's
// rdp->cblist
rcu_do_batch()
// invoke CPU1's rdp->cblist
// callback
rcu_barrier_callback()
rcu_barrier()
mutex_lock(&rcu_state.barrier_mutex);
// still see len == 2
// enqueue barrier callback
// to CPU1's rdp->cblist
rcu_segcblist_entrain()
rcu_segcblist_add_len(1);
// len == 3
// decrement len
rcu_segcblist_add_len(-2);
kthread_parkme()
// CPU1's rdp->cblist len == 1
// Warn because there is
// still a pending barrier
// trigger warning
WARN_ON_ONCE(rcu_segcblist_n_cbs(&rdp->cblist));
cpus_read_unlock();
// wait CPU1 to comes online and
// invoke barrier callback on
// CPU1 rdp's->cblist
wait_for_completion(&rcu_state.barrier_completion);
// deoffload CPU4
cpus_read_lock()
rcu_barrier()
mutex_lock(&rcu_state.barrier_mutex);
// block on barrier_mutex
// wait rcu_barrier() on
// CPU3 to unlock barrier_mutex
// but CPU3 unlock barrier_mutex
// need to wait CPU1 comes online
// when CPU1 going online will block on cpus_write_lock
The above scenario will not only trigger a WARN_ON_ONCE(), but also
trigger a deadlock.
Thanks to nocb locking, a second racing rcu_barrier() on an offline CPU
will either observe the decremented callback counter down to 0 and spare
the callback enqueue, or rcuo will observe the new callback and keep
rdp->nocb_cb_sleep to false.
Therefore check rdp->nocb_cb_sleep before parking to make sure no
further rcu_barrier() is waiting on the rdp.
In the Linux kernel, the following vulnerability has been resolved:
drivers: soc: xilinx: add the missing kfree in xlnx_add_cb_for_suspend()
If we fail to allocate memory for cb_data by kmalloc, the memory
allocation for eve_data is never freed, add the missing kfree()
in the error handling path.
In the Linux kernel, the following vulnerability has been resolved:
HID: hyperv: streamline driver probe to avoid devres issues
It was found that unloading 'hid_hyperv' module results in a devres
complaint:
...
hv_vmbus: unregistering driver hid_hyperv
------------[ cut here ]------------
WARNING: CPU: 2 PID: 3983 at drivers/base/devres.c:691 devres_release_group+0x1f2/0x2c0
...
Call Trace:
<TASK>
? devres_release_group+0x1f2/0x2c0
? __warn+0xd1/0x1c0
? devres_release_group+0x1f2/0x2c0
? report_bug+0x32a/0x3c0
? handle_bug+0x53/0xa0
? exc_invalid_op+0x18/0x50
? asm_exc_invalid_op+0x1a/0x20
? devres_release_group+0x1f2/0x2c0
? devres_release_group+0x90/0x2c0
? rcu_is_watching+0x15/0xb0
? __pfx_devres_release_group+0x10/0x10
hid_device_remove+0xf5/0x220
device_release_driver_internal+0x371/0x540
? klist_put+0xf3/0x170
bus_remove_device+0x1f1/0x3f0
device_del+0x33f/0x8c0
? __pfx_device_del+0x10/0x10
? cleanup_srcu_struct+0x337/0x500
hid_destroy_device+0xc8/0x130
mousevsc_remove+0xd2/0x1d0 [hid_hyperv]
device_release_driver_internal+0x371/0x540
driver_detach+0xc5/0x180
bus_remove_driver+0x11e/0x2a0
? __mutex_unlock_slowpath+0x160/0x5e0
vmbus_driver_unregister+0x62/0x2b0 [hv_vmbus]
...
And the issue seems to be that the corresponding devres group is not
allocated. Normally, devres_open_group() is called from
__hid_device_probe() but Hyper-V HID driver overrides 'hid_dev->driver'
with 'mousevsc_hid_driver' stub and basically re-implements
__hid_device_probe() by calling hid_parse() and hid_hw_start() but not
devres_open_group(). hid_device_probe() does not call __hid_device_probe()
for it. Later, when the driver is removed, hid_device_remove() calls
devres_release_group() as it doesn't check whether hdev->driver was
initially overridden or not.
The issue seems to be related to the commit 62c68e7cee33 ("HID: ensure
timely release of driver-allocated resources") but the commit itself seems
to be correct.
Fix the issue by dropping the 'hid_dev->driver' override and using
hid_register_driver()/hid_unregister_driver() instead. Alternatively, it
would have been possible to rely on the default handling but
HID_CONNECT_DEFAULT implies HID_CONNECT_HIDRAW and it doesn't seem to work
for mousevsc as-is.
In the Linux kernel, the following vulnerability has been resolved:
udmabuf: change folios array from kmalloc to kvmalloc
When PAGE_SIZE 4096, MAX_PAGE_ORDER 10, 64bit machine,
page_alloc only support 4MB.
If above this, trigger this warn and return NULL.
udmabuf can change size limit, if change it to 3072(3GB), and then alloc
3GB udmabuf, will fail create.
[ 4080.876581] ------------[ cut here ]------------
[ 4080.876843] WARNING: CPU: 3 PID: 2015 at mm/page_alloc.c:4556 __alloc_pages+0x2c8/0x350
[ 4080.878839] RIP: 0010:__alloc_pages+0x2c8/0x350
[ 4080.879470] Call Trace:
[ 4080.879473] <TASK>
[ 4080.879473] ? __alloc_pages+0x2c8/0x350
[ 4080.879475] ? __warn.cold+0x8e/0xe8
[ 4080.880647] ? __alloc_pages+0x2c8/0x350
[ 4080.880909] ? report_bug+0xff/0x140
[ 4080.881175] ? handle_bug+0x3c/0x80
[ 4080.881556] ? exc_invalid_op+0x17/0x70
[ 4080.881559] ? asm_exc_invalid_op+0x1a/0x20
[ 4080.882077] ? udmabuf_create+0x131/0x400
Because MAX_PAGE_ORDER, kmalloc can max alloc 4096 * (1 << 10), 4MB
memory, each array entry is pointer(8byte), so can save 524288 pages(2GB).
Further more, costly order(order 3) may not be guaranteed that it can be
applied for, due to fragmentation.
This patch change udmabuf array use kvmalloc_array, this can fallback
alloc into vmalloc, which can guarantee allocation for any size and does
not affect the performance of kmalloc allocations.