| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
workqueue: Do not warn when cancelling WQ_MEM_RECLAIM work from !WQ_MEM_RECLAIM worker
After commit
746ae46c1113 ("drm/sched: Mark scheduler work queues with WQ_MEM_RECLAIM")
amdgpu started seeing the following warning:
[ ] workqueue: WQ_MEM_RECLAIM sdma0:drm_sched_run_job_work [gpu_sched] is flushing !WQ_MEM_RECLAIM events:amdgpu_device_delay_enable_gfx_off [amdgpu]
...
[ ] Workqueue: sdma0 drm_sched_run_job_work [gpu_sched]
...
[ ] Call Trace:
[ ] <TASK>
...
[ ] ? check_flush_dependency+0xf5/0x110
...
[ ] cancel_delayed_work_sync+0x6e/0x80
[ ] amdgpu_gfx_off_ctrl+0xab/0x140 [amdgpu]
[ ] amdgpu_ring_alloc+0x40/0x50 [amdgpu]
[ ] amdgpu_ib_schedule+0xf4/0x810 [amdgpu]
[ ] ? drm_sched_run_job_work+0x22c/0x430 [gpu_sched]
[ ] amdgpu_job_run+0xaa/0x1f0 [amdgpu]
[ ] drm_sched_run_job_work+0x257/0x430 [gpu_sched]
[ ] process_one_work+0x217/0x720
...
[ ] </TASK>
The intent of the verifcation done in check_flush_depedency is to ensure
forward progress during memory reclaim, by flagging cases when either a
memory reclaim process, or a memory reclaim work item is flushed from a
context not marked as memory reclaim safe.
This is correct when flushing, but when called from the
cancel(_delayed)_work_sync() paths it is a false positive because work is
either already running, or will not be running at all. Therefore
cancelling it is safe and we can relax the warning criteria by letting the
helper know of the calling context.
References: 746ae46c1113 ("drm/sched: Mark scheduler work queues with WQ_MEM_RECLAIM") |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: mpi3mr: Fix corrupt config pages PHY state is switched in sysfs
The driver, through the SAS transport, exposes a sysfs interface to
enable/disable PHYs in a controller/expander setup. When multiple PHYs
are disabled and enabled in rapid succession, the persistent and current
config pages related to SAS IO unit/SAS Expander pages could get
corrupted.
Use separate memory for each config request. |
| 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:
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:
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:
KVM: arm64: Get rid of userspace_irqchip_in_use
Improper use of userspace_irqchip_in_use led to syzbot hitting the
following WARN_ON() in kvm_timer_update_irq():
WARNING: CPU: 0 PID: 3281 at arch/arm64/kvm/arch_timer.c:459
kvm_timer_update_irq+0x21c/0x394
Call trace:
kvm_timer_update_irq+0x21c/0x394 arch/arm64/kvm/arch_timer.c:459
kvm_timer_vcpu_reset+0x158/0x684 arch/arm64/kvm/arch_timer.c:968
kvm_reset_vcpu+0x3b4/0x560 arch/arm64/kvm/reset.c:264
kvm_vcpu_set_target arch/arm64/kvm/arm.c:1553 [inline]
kvm_arch_vcpu_ioctl_vcpu_init arch/arm64/kvm/arm.c:1573 [inline]
kvm_arch_vcpu_ioctl+0x112c/0x1b3c arch/arm64/kvm/arm.c:1695
kvm_vcpu_ioctl+0x4ec/0xf74 virt/kvm/kvm_main.c:4658
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__arm64_sys_ioctl+0x108/0x184 fs/ioctl.c:893
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x78/0x1b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x1b0 arch/arm64/kernel/syscall.c:132
do_el0_svc+0x40/0x50 arch/arm64/kernel/syscall.c:151
el0_svc+0x54/0x14c arch/arm64/kernel/entry-common.c:712
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
The following sequence led to the scenario:
- Userspace creates a VM and a vCPU.
- The vCPU is initialized with KVM_ARM_VCPU_PMU_V3 during
KVM_ARM_VCPU_INIT.
- Without any other setup, such as vGIC or vPMU, userspace issues
KVM_RUN on the vCPU. Since the vPMU is requested, but not setup,
kvm_arm_pmu_v3_enable() fails in kvm_arch_vcpu_run_pid_change().
As a result, KVM_RUN returns after enabling the timer, but before
incrementing 'userspace_irqchip_in_use':
kvm_arch_vcpu_run_pid_change()
ret = kvm_arm_pmu_v3_enable()
if (!vcpu->arch.pmu.created)
return -EINVAL;
if (ret)
return ret;
[...]
if (!irqchip_in_kernel(kvm))
static_branch_inc(&userspace_irqchip_in_use);
- Userspace ignores the error and issues KVM_ARM_VCPU_INIT again.
Since the timer is already enabled, control moves through the
following flow, ultimately hitting the WARN_ON():
kvm_timer_vcpu_reset()
if (timer->enabled)
kvm_timer_update_irq()
if (!userspace_irqchip())
ret = kvm_vgic_inject_irq()
ret = vgic_lazy_init()
if (unlikely(!vgic_initialized(kvm)))
if (kvm->arch.vgic.vgic_model !=
KVM_DEV_TYPE_ARM_VGIC_V2)
return -EBUSY;
WARN_ON(ret);
Theoretically, since userspace_irqchip_in_use's functionality can be
simply replaced by '!irqchip_in_kernel()', get rid of the static key
to avoid the mismanagement, which also helps with the syzbot issue. |
| In the Linux kernel, the following vulnerability has been resolved:
x86/CPU/AMD: Clear virtualized VMLOAD/VMSAVE on Zen4 client
A number of Zen4 client SoCs advertise the ability to use virtualized
VMLOAD/VMSAVE, but using these instructions is reported to be a cause
of a random host reboot.
These instructions aren't intended to be advertised on Zen4 client
so clear the capability. |
| In the Linux kernel, the following vulnerability has been resolved:
RDMA/siw: Add sendpage_ok() check to disable MSG_SPLICE_PAGES
While running ISER over SIW, the initiator machine encounters a warning
from skb_splice_from_iter() indicating that a slab page is being used in
send_page. To address this, it is better to add a sendpage_ok() check
within the driver itself, and if it returns 0, then MSG_SPLICE_PAGES flag
should be disabled before entering the network stack.
A similar issue has been discussed for NVMe in this thread:
https://lore.kernel.org/all/20240530142417.146696-1-ofir.gal@volumez.com/
WARNING: CPU: 0 PID: 5342 at net/core/skbuff.c:7140 skb_splice_from_iter+0x173/0x320
Call Trace:
tcp_sendmsg_locked+0x368/0xe40
siw_tx_hdt+0x695/0xa40 [siw]
siw_qp_sq_process+0x102/0xb00 [siw]
siw_sq_resume+0x39/0x110 [siw]
siw_run_sq+0x74/0x160 [siw]
kthread+0xd2/0x100
ret_from_fork+0x34/0x40
ret_from_fork_asm+0x1a/0x30 |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Add sk_is_inet and IS_ICSK check in tls_sw_has_ctx_tx/rx
As the introduction of the support for vsock and unix sockets in sockmap,
tls_sw_has_ctx_tx/rx cannot presume the socket passed in must be IS_ICSK.
vsock and af_unix sockets have vsock_sock and unix_sock instead of
inet_connection_sock. For these sockets, tls_get_ctx may return an invalid
pointer and cause page fault in function tls_sw_ctx_rx.
BUG: unable to handle page fault for address: 0000000000040030
Workqueue: vsock-loopback vsock_loopback_work
RIP: 0010:sk_psock_strp_data_ready+0x23/0x60
Call Trace:
? __die+0x81/0xc3
? no_context+0x194/0x350
? do_page_fault+0x30/0x110
? async_page_fault+0x3e/0x50
? sk_psock_strp_data_ready+0x23/0x60
virtio_transport_recv_pkt+0x750/0x800
? update_load_avg+0x7e/0x620
vsock_loopback_work+0xd0/0x100
process_one_work+0x1a7/0x360
worker_thread+0x30/0x390
? create_worker+0x1a0/0x1a0
kthread+0x112/0x130
? __kthread_cancel_work+0x40/0x40
ret_from_fork+0x1f/0x40
v2:
- Add IS_ICSK check
v3:
- Update the commits in Fixes |
| In the Linux kernel, the following vulnerability has been resolved:
drm/i915/hdcp: Add encoder check in intel_hdcp_get_capability
Sometimes during hotplug scenario or suspend/resume scenario encoder is
not always initialized when intel_hdcp_get_capability add
a check to avoid kernel null pointer dereference. |
| In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Mark inode as bad as soon as error detected in mi_enum_attr()
Extended the `mi_enum_attr()` function interface with an additional
parameter, `struct ntfs_inode *ni`, to allow marking the inode
as bad as soon as an error is detected. |
| In the Linux kernel, the following vulnerability has been resolved:
media: av7110: fix a spectre vulnerability
As warned by smatch:
drivers/staging/media/av7110/av7110_ca.c:270 dvb_ca_ioctl() warn: potential spectre issue 'av7110->ci_slot' [w] (local cap)
There is a spectre-related vulnerability at the code. Fix it. |
| In the Linux kernel, the following vulnerability has been resolved:
l2tp: prevent possible tunnel refcount underflow
When a session is created, it sets a backpointer to its tunnel. When
the session refcount drops to 0, l2tp_session_free drops the tunnel
refcount if session->tunnel is non-NULL. However, session->tunnel is
set in l2tp_session_create, before the tunnel refcount is incremented
by l2tp_session_register, which leaves a small window where
session->tunnel is non-NULL when the tunnel refcount hasn't been
bumped.
Moving the assignment to l2tp_session_register is trivial but
l2tp_session_create calls l2tp_session_set_header_len which uses
session->tunnel to get the tunnel's encap. Add an encap arg to
l2tp_session_set_header_len to avoid using session->tunnel.
If l2tpv3 sessions have colliding IDs, it is possible for
l2tp_v3_session_get to race with l2tp_session_register and fetch a
session which doesn't yet have session->tunnel set. Add a check for
this case. |
| In the Linux kernel, the following vulnerability has been resolved:
rcu-tasks: Fix access non-existent percpu rtpcp variable in rcu_tasks_need_gpcb()
For kernels built with CONFIG_FORCE_NR_CPUS=y, the nr_cpu_ids is
defined as NR_CPUS instead of the number of possible cpus, this
will cause the following system panic:
smpboot: Allowing 4 CPUs, 0 hotplug CPUs
...
setup_percpu: NR_CPUS:512 nr_cpumask_bits:512 nr_cpu_ids:512 nr_node_ids:1
...
BUG: unable to handle page fault for address: ffffffff9911c8c8
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 PID: 15 Comm: rcu_tasks_trace Tainted: G W
6.6.21 #1 5dc7acf91a5e8e9ac9dcfc35bee0245691283ea6
RIP: 0010:rcu_tasks_need_gpcb+0x25d/0x2c0
RSP: 0018:ffffa371c00a3e60 EFLAGS: 00010082
CR2: ffffffff9911c8c8 CR3: 000000040fa20005 CR4: 00000000001706f0
Call Trace:
<TASK>
? __die+0x23/0x80
? page_fault_oops+0xa4/0x180
? exc_page_fault+0x152/0x180
? asm_exc_page_fault+0x26/0x40
? rcu_tasks_need_gpcb+0x25d/0x2c0
? __pfx_rcu_tasks_kthread+0x40/0x40
rcu_tasks_one_gp+0x69/0x180
rcu_tasks_kthread+0x94/0xc0
kthread+0xe8/0x140
? __pfx_kthread+0x40/0x40
ret_from_fork+0x34/0x80
? __pfx_kthread+0x40/0x40
ret_from_fork_asm+0x1b/0x80
</TASK>
Considering that there may be holes in the CPU numbers, use the
maximum possible cpu number, instead of nr_cpu_ids, for configuring
enqueue and dequeue limits.
[ neeraj.upadhyay: Fix htmldocs build error reported by Stephen Rothwell ] |
| In the Linux kernel, the following vulnerability has been resolved:
nvme-rdma: unquiesce admin_q before destroy it
Kernel will hang on destroy admin_q while we create ctrl failed, such
as following calltrace:
PID: 23644 TASK: ff2d52b40f439fc0 CPU: 2 COMMAND: "nvme"
#0 [ff61d23de260fb78] __schedule at ffffffff8323bc15
#1 [ff61d23de260fc08] schedule at ffffffff8323c014
#2 [ff61d23de260fc28] blk_mq_freeze_queue_wait at ffffffff82a3dba1
#3 [ff61d23de260fc78] blk_freeze_queue at ffffffff82a4113a
#4 [ff61d23de260fc90] blk_cleanup_queue at ffffffff82a33006
#5 [ff61d23de260fcb0] nvme_rdma_destroy_admin_queue at ffffffffc12686ce
#6 [ff61d23de260fcc8] nvme_rdma_setup_ctrl at ffffffffc1268ced
#7 [ff61d23de260fd28] nvme_rdma_create_ctrl at ffffffffc126919b
#8 [ff61d23de260fd68] nvmf_dev_write at ffffffffc024f362
#9 [ff61d23de260fe38] vfs_write at ffffffff827d5f25
RIP: 00007fda7891d574 RSP: 00007ffe2ef06958 RFLAGS: 00000202
RAX: ffffffffffffffda RBX: 000055e8122a4d90 RCX: 00007fda7891d574
RDX: 000000000000012b RSI: 000055e8122a4d90 RDI: 0000000000000004
RBP: 00007ffe2ef079c0 R8: 000000000000012b R9: 000055e8122a4d90
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000004
R13: 000055e8122923c0 R14: 000000000000012b R15: 00007fda78a54500
ORIG_RAX: 0000000000000001 CS: 0033 SS: 002b
This due to we have quiesced admi_q before cancel requests, but forgot
to unquiesce before destroy it, as a result we fail to drain the
pending requests, and hang on blk_mq_freeze_queue_wait() forever. Here
try to reuse nvme_rdma_teardown_admin_queue() to fix this issue and
simplify the code. |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: stm32/cryp - call finalize with bh disabled
The finalize operation in interrupt mode produce a produces a spinlock
recursion warning. The reason is the fact that BH must be disabled
during this process. |
| In the Linux kernel, the following vulnerability has been resolved:
ethtool: fail closed if we can't get max channel used in indirection tables
Commit 0d1b7d6c9274 ("bnxt: fix crashes when reducing ring count with
active RSS contexts") proves that allowing indirection table to contain
channels with out of bounds IDs may lead to crashes. Currently the
max channel check in the core gets skipped if driver can't fetch
the indirection table or when we can't allocate memory.
Both of those conditions should be extremely rare but if they do
happen we should try to be safe and fail the channel change. |
| In the Linux kernel, the following vulnerability has been resolved:
userfaultfd: fix checks for huge PMDs
Patch series "userfaultfd: fix races around pmd_trans_huge() check", v2.
The pmd_trans_huge() code in mfill_atomic() is wrong in three different
ways depending on kernel version:
1. The pmd_trans_huge() check is racy and can lead to a BUG_ON() (if you hit
the right two race windows) - I've tested this in a kernel build with
some extra mdelay() calls. See the commit message for a description
of the race scenario.
On older kernels (before 6.5), I think the same bug can even
theoretically lead to accessing transhuge page contents as a page table
if you hit the right 5 narrow race windows (I haven't tested this case).
2. As pointed out by Qi Zheng, pmd_trans_huge() is not sufficient for
detecting PMDs that don't point to page tables.
On older kernels (before 6.5), you'd just have to win a single fairly
wide race to hit this.
I've tested this on 6.1 stable by racing migration (with a mdelay()
patched into try_to_migrate()) against UFFDIO_ZEROPAGE - on my x86
VM, that causes a kernel oops in ptlock_ptr().
3. On newer kernels (>=6.5), for shmem mappings, khugepaged is allowed
to yank page tables out from under us (though I haven't tested that),
so I think the BUG_ON() checks in mfill_atomic() are just wrong.
I decided to write two separate fixes for these (one fix for bugs 1+2, one
fix for bug 3), so that the first fix can be backported to kernels
affected by bugs 1+2.
This patch (of 2):
This fixes two issues.
I discovered that the following race can occur:
mfill_atomic other thread
============ ============
<zap PMD>
pmdp_get_lockless() [reads none pmd]
<bail if trans_huge>
<if none:>
<pagefault creates transhuge zeropage>
__pte_alloc [no-op]
<zap PMD>
<bail if pmd_trans_huge(*dst_pmd)>
BUG_ON(pmd_none(*dst_pmd))
I have experimentally verified this in a kernel with extra mdelay() calls;
the BUG_ON(pmd_none(*dst_pmd)) triggers.
On kernels newer than commit 0d940a9b270b ("mm/pgtable: allow
pte_offset_map[_lock]() to fail"), this can't lead to anything worse than
a BUG_ON(), since the page table access helpers are actually designed to
deal with page tables concurrently disappearing; but on older kernels
(<=6.4), I think we could probably theoretically race past the two
BUG_ON() checks and end up treating a hugepage as a page table.
The second issue is that, as Qi Zheng pointed out, there are other types
of huge PMDs that pmd_trans_huge() can't catch: devmap PMDs and swap PMDs
(in particular, migration PMDs).
On <=6.4, this is worse than the first issue: If mfill_atomic() runs on a
PMD that contains a migration entry (which just requires winning a single,
fairly wide race), it will pass the PMD to pte_offset_map_lock(), which
assumes that the PMD points to a page table.
Breakage follows: First, the kernel tries to take the PTE lock (which will
crash or maybe worse if there is no "struct page" for the address bits in
the migration entry PMD - I think at least on X86 there usually is no
corresponding "struct page" thanks to the PTE inversion mitigation, amd64
looks different).
If that didn't crash, the kernel would next try to write a PTE into what
it wrongly thinks is a page table.
As part of fixing these issues, get rid of the check for pmd_trans_huge()
before __pte_alloc() - that's redundant, we're going to have to check for
that after the __pte_alloc() anyway.
Backport note: pmdp_get_lockless() is pmd_read_atomic() in older kernels. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Validate function returns
[WHAT & HOW]
Function return values must be checked before data can be used
in subsequent functions.
This fixes 4 CHECKED_RETURN issues reported by Coverity. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Check index for aux_rd_interval before using
aux_rd_interval has size of 7 and should be checked.
This fixes 3 OVERRUN and 1 INTEGER_OVERFLOW issues reported by Coverity. |
