Search Results (18044 CVEs found)

CVE Vendors Products Updated CVSS v3.1
CVE-2022-50826 1 Linux 1 Linux Kernel 2026-04-15 N/A
In the Linux kernel, the following vulnerability has been resolved: ipu3-imgu: Fix NULL pointer dereference in imgu_subdev_set_selection() Calling v4l2_subdev_get_try_crop() and v4l2_subdev_get_try_compose() with a subdev state of NULL leads to a NULL pointer dereference. This can currently happen in imgu_subdev_set_selection() when the state passed in is NULL, as this method first gets pointers to both the "try" and "active" states and only then decides which to use. The same issue has been addressed for imgu_subdev_get_selection() with commit 30d03a0de650 ("ipu3-imgu: Fix NULL pointer dereference in active selection access"). However the issue still persists in imgu_subdev_set_selection(). Therefore, apply a similar fix as done in the aforementioned commit to imgu_subdev_set_selection(). To keep things a bit cleaner, introduce helper functions for "crop" and "compose" access and use them in both imgu_subdev_set_selection() and imgu_subdev_get_selection().
CVE-2022-50814 1 Linux 1 Linux Kernel 2026-04-15 N/A
In the Linux kernel, the following vulnerability has been resolved: crypto: hisilicon/zip - fix mismatch in get/set sgl_sge_nr KASAN reported this Bug: [17619.659757] BUG: KASAN: global-out-of-bounds in param_get_int+0x34/0x60 [17619.673193] Read of size 4 at addr fffff01332d7ed00 by task read_all/1507958 ... [17619.698934] The buggy address belongs to the variable: [17619.708371] sgl_sge_nr+0x0/0xffffffffffffa300 [hisi_zip] There is a mismatch in hisi_zip when get/set the variable sgl_sge_nr. The type of sgl_sge_nr is u16, and get/set sgl_sge_nr by param_get/set_int. Replacing param_get/set_int to param_get/set_ushort can fix this bug.
CVE-2022-50818 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: scsi: pm8001: Fix running_req for internal abort commands Disabling the remote phy for a SATA disk causes a hang: root@(none)$ more /sys/class/sas_phy/phy-0:0:8/target_port_protocols sata root@(none)$ echo 0 > sys/class/sas_phy/phy-0:0:8/enable root@(none)$ [ 67.855950] sas: ex 500e004aaaaaaa1f phy08 change count has changed [ 67.920585] sd 0:0:2:0: [sdc] Synchronizing SCSI cache [ 67.925780] sd 0:0:2:0: [sdc] Synchronize Cache(10) failed: Result: hostbyte=0x04 driverbyte=DRIVER_OK [ 67.935094] sd 0:0:2:0: [sdc] Stopping disk [ 67.939305] sd 0:0:2:0: [sdc] Start/Stop Unit failed: Result: hostbyte=0x04 driverbyte=DRIVER_OK ... [ 123.998998] INFO: task kworker/u192:1:642 blocked for more than 30 seconds. [ 124.005960] Not tainted 6.0.0-rc1-205202-gf26f8f761e83 #218 [ 124.012049] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 124.019872] task:kworker/u192:1 state:D stack:0 pid: 642 ppid: 2 flags:0x00000008 [ 124.028223] Workqueue: 0000:04:00.0_event_q sas_port_event_worker [ 124.034319] Call trace: [ 124.036758] __switch_to+0x128/0x278 [ 124.040333] __schedule+0x434/0xa58 [ 124.043820] schedule+0x94/0x138 [ 124.047045] schedule_timeout+0x2fc/0x368 [ 124.051052] wait_for_completion+0xdc/0x200 [ 124.055234] __flush_workqueue+0x1a8/0x708 [ 124.059328] sas_porte_broadcast_rcvd+0xa8/0xc0 [ 124.063858] sas_port_event_worker+0x60/0x98 [ 124.068126] process_one_work+0x3f8/0x660 [ 124.072134] worker_thread+0x70/0x700 [ 124.075793] kthread+0x1a4/0x1b8 [ 124.079014] ret_from_fork+0x10/0x20 The issue is that the per-device running_req read in pm8001_dev_gone_notify() never goes to zero and we never make progress. This is caused by missing accounting for running_req for when an internal abort command completes. In commit 2cbbf489778e ("scsi: pm8001: Use libsas internal abort support") we started to send internal abort commands as a proper sas_task. In this when we deliver a sas_task to HW the per-device running_req is incremented in pm8001_queue_command(). However it is never decremented for internal abort commnds, so decrement in pm8001_mpi_task_abort_resp().
CVE-2025-40142 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Disable bottom softirqs as part of spin_lock_irq() on PREEMPT_RT snd_pcm_group_lock_irq() acquires a spinlock_t and disables interrupts via spin_lock_irq(). This also implicitly disables the handling of softirqs such as TIMER_SOFTIRQ. On PREEMPT_RT softirqs are preemptible and spin_lock_irq() does not disable them. That means a timer can be invoked during spin_lock_irq() on the same CPU. Due to synchronisations reasons local_bh_disable() has a per-CPU lock named softirq_ctrl.lock which synchronizes individual softirq against each other. syz-bot managed to trigger a lockdep report where softirq_ctrl.lock is acquired in hrtimer_cancel() in addition to hrtimer_run_softirq(). This is a possible deadlock. The softirq_ctrl.lock can not be made part of spin_lock_irq() as this would lead to too much synchronisation against individual threads on the system. To avoid the possible deadlock, softirqs must be manually disabled before the lock is acquired. Disable softirqs before the lock is acquired on PREEMPT_RT.
CVE-2025-40287 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: exfat: fix improper check of dentry.stream.valid_size We found an infinite loop bug in the exFAT file system that can lead to a Denial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is malformed, the following system calls — SYS_openat, SYS_ftruncate, and SYS_pwrite64 — can cause the kernel to hang. Root cause analysis shows that the size validation code in exfat_find() does not check whether dentry.stream.valid_size is negative. As a result, the system calls mentioned above can succeed and eventually trigger the DoS issue. This patch adds a check for negative dentry.stream.valid_size to prevent this vulnerability.
CVE-2025-40284 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: MGMT: cancel mesh send timer when hdev removed mesh_send_done timer is not canceled when hdev is removed, which causes crash if the timer triggers after hdev is gone. Cancel the timer when MGMT removes the hdev, like other MGMT timers. Should fix the BUG: sporadically seen by BlueZ test bot (in "Mesh - Send cancel - 1" test). Log: ------ BUG: KASAN: slab-use-after-free in run_timer_softirq+0x76b/0x7d0 ... Freed by task 36: kasan_save_stack+0x24/0x50 kasan_save_track+0x14/0x30 __kasan_save_free_info+0x3a/0x60 __kasan_slab_free+0x43/0x70 kfree+0x103/0x500 device_release+0x9a/0x210 kobject_put+0x100/0x1e0 vhci_release+0x18b/0x240 ------
CVE-2025-40272 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: fix use-after-free race in fault handler When a page fault occurs in a secret memory file created with `memfd_secret(2)`, the kernel will allocate a new folio for it, mark the underlying page as not-present in the direct map, and add it to the file mapping. If two tasks cause a fault in the same page concurrently, both could end up allocating a folio and removing the page from the direct map, but only one would succeed in adding the folio to the file mapping. The task that failed undoes the effects of its attempt by (a) freeing the folio again and (b) putting the page back into the direct map. However, by doing these two operations in this order, the page becomes available to the allocator again before it is placed back in the direct mapping. If another task attempts to allocate the page between (a) and (b), and the kernel tries to access it via the direct map, it would result in a supervisor not-present page fault. Fix the ordering to restore the direct map before the folio is freed.
CVE-2025-40110 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: drm/vmwgfx: Fix a null-ptr access in the cursor snooper Check that the resource which is converted to a surface exists before trying to use the cursor snooper on it. vmw_cmd_res_check allows explicit invalid (SVGA3D_INVALID_ID) identifiers because some svga commands accept SVGA3D_INVALID_ID to mean "no surface", unfortunately functions that accept the actual surfaces as objects might (and in case of the cursor snooper, do not) be able to handle null objects. Make sure that we validate not only the identifier (via the vmw_cmd_res_check) but also check that the actual resource exists before trying to do something with it. Fixes unchecked null-ptr reference in the snooping code.
CVE-2025-40271 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: fs/proc: fix uaf in proc_readdir_de() Pde is erased from subdir rbtree through rb_erase(), but not set the node to EMPTY, which may result in uaf access. We should use RB_CLEAR_NODE() set the erased node to EMPTY, then pde_subdir_next() will return NULL to avoid uaf access. We found an uaf issue while using stress-ng testing, need to run testcase getdent and tun in the same time. The steps of the issue is as follows: 1) use getdent to traverse dir /proc/pid/net/dev_snmp6/, and current pde is tun3; 2) in the [time windows] unregister netdevice tun3 and tun2, and erase them from rbtree. erase tun3 first, and then erase tun2. the pde(tun2) will be released to slab; 3) continue to getdent process, then pde_subdir_next() will return pde(tun2) which is released, it will case uaf access. CPU 0 | CPU 1 ------------------------------------------------------------------------- traverse dir /proc/pid/net/dev_snmp6/ | unregister_netdevice(tun->dev) //tun3 tun2 sys_getdents64() | iterate_dir() | proc_readdir() | proc_readdir_de() | snmp6_unregister_dev() pde_get(de); | proc_remove() read_unlock(&proc_subdir_lock); | remove_proc_subtree() | write_lock(&proc_subdir_lock); [time window] | rb_erase(&root->subdir_node, &parent->subdir); | write_unlock(&proc_subdir_lock); read_lock(&proc_subdir_lock); | next = pde_subdir_next(de); | pde_put(de); | de = next; //UAF | rbtree of dev_snmp6 | pde(tun3) / \ NULL pde(tun2)
CVE-2025-40270 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: mm, swap: fix potential UAF issue for VMA readahead Since commit 78524b05f1a3 ("mm, swap: avoid redundant swap device pinning"), the common helper for allocating and preparing a folio in the swap cache layer no longer tries to get a swap device reference internally, because all callers of __read_swap_cache_async are already holding a swap entry reference. The repeated swap device pinning isn't needed on the same swap device. Caller of VMA readahead is also holding a reference to the target entry's swap device, but VMA readahead walks the page table, so it might encounter swap entries from other devices, and call __read_swap_cache_async on another device without holding a reference to it. So it is possible to cause a UAF when swapoff of device A raced with swapin on device B, and VMA readahead tries to read swap entries from device A. It's not easy to trigger, but in theory, it could cause real issues. Make VMA readahead try to get the device reference first if the swap device is a different one from the target entry.
CVE-2025-40268 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: cifs: client: fix memory leak in smb3_fs_context_parse_param The user calls fsconfig twice, but when the program exits, free() only frees ctx->source for the second fsconfig, not the first. Regarding fc->source, there is no code in the fs context related to its memory reclamation. To fix this memory leak, release the source memory corresponding to ctx or fc before each parsing. syzbot reported: BUG: memory leak unreferenced object 0xffff888128afa360 (size 96): backtrace (crc 79c9c7ba): kstrdup+0x3c/0x80 mm/util.c:84 smb3_fs_context_parse_param+0x229b/0x36c0 fs/smb/client/fs_context.c:1444 BUG: memory leak unreferenced object 0xffff888112c7d900 (size 96): backtrace (crc 79c9c7ba): smb3_fs_context_fullpath+0x70/0x1b0 fs/smb/client/fs_context.c:629 smb3_fs_context_parse_param+0x2266/0x36c0 fs/smb/client/fs_context.c:1438
CVE-2025-40124 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: sparc: fix accurate exception reporting in copy_{from_to}_user for UltraSPARC III Anthony Yznaga tracked down that a BUG_ON in ext4 code with large folios enabled resulted from copy_from_user() returning impossibly large values greater than the size to be copied. This lead to __copy_from_iter() returning impossible values instead of the actual number of bytes it was able to copy. The BUG_ON has been reported in https://lore.kernel.org/r/b14f55642207e63e907965e209f6323a0df6dcee.camel@physik.fu-berlin.de The referenced commit introduced exception handlers on user-space memory references in copy_from_user and copy_to_user. These handlers return from the respective function and calculate the remaining bytes left to copy using the current register contents. The exception handlers expect that %o2 has already been masked during the bulk copy loop, but the masking was performed after that loop. This will fix the return value of copy_from_user and copy_to_user in the faulting case. The behaviour of memcpy stays unchanged.
CVE-2025-40212 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix refcount leak in nfsd_set_fh_dentry() nfsd exports a "pseudo root filesystem" which is used by NFSv4 to find the various exported filesystems using LOOKUP requests from a known root filehandle. NFSv3 uses the MOUNT protocol to find those exported filesystems and so is not given access to the pseudo root filesystem. If a v3 (or v2) client uses a filehandle from that filesystem, nfsd_set_fh_dentry() will report an error, but still stores the export in "struct svc_fh" even though it also drops the reference (exp_put()). This means that when fh_put() is called an extra reference will be dropped which can lead to use-after-free and possible denial of service. Normal NFS usage will not provide a pseudo-root filehandle to a v3 client. This bug can only be triggered by the client synthesising an incorrect filehandle. To fix this we move the assignments to the svc_fh later, after all possible error cases have been detected.
CVE-2025-68331 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: usb: uas: fix urb unmapping issue when the uas device is remove during ongoing data transfer When a UAS device is unplugged during data transfer, there is a probability of a system panic occurring. The root cause is an access to an invalid memory address during URB callback handling. Specifically, this happens when the dma_direct_unmap_sg() function is called within the usb_hcd_unmap_urb_for_dma() interface, but the sg->dma_address field is 0 and the sg data structure has already been freed. The SCSI driver sends transfer commands by invoking uas_queuecommand_lck() in uas.c, using the uas_submit_urbs() function to submit requests to USB. Within the uas_submit_urbs() implementation, three URBs (sense_urb, data_urb, and cmd_urb) are sequentially submitted. Device removal may occur at any point during uas_submit_urbs execution, which may result in URB submission failure. However, some URBs might have been successfully submitted before the failure, and uas_submit_urbs will return the -ENODEV error code in this case. The current error handling directly calls scsi_done(). In the SCSI driver, this eventually triggers scsi_complete() to invoke scsi_end_request() for releasing the sgtable. The successfully submitted URBs, when being unlinked to giveback, call usb_hcd_unmap_urb_for_dma() in hcd.c, leading to exceptions during sg unmapping operations since the sg data structure has already been freed. This patch modifies the error condition check in the uas_submit_urbs() function. When a UAS device is removed but one or more URBs have already been successfully submitted to USB, it avoids immediately invoking scsi_done() and save the cmnd to devinfo->cmnd array. If the successfully submitted URBs is completed before devinfo->resetting being set, then the scsi_done() function will be called within uas_try_complete() after all pending URB operations are finalized. Otherwise, the scsi_done() function will be called within uas_zap_pending(), which is executed after usb_kill_anchored_urbs(). The error handling only takes effect when uas_queuecommand_lck() calls uas_submit_urbs() and returns the error value -ENODEV . In this case, the device is disconnected, and the flow proceeds to uas_disconnect(), where uas_zap_pending() is invoked to call uas_try_complete().
CVE-2025-40148 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Add NULL pointer checks in dc_stream cursor attribute functions The function dc_stream_set_cursor_attributes() currently dereferences the `stream` pointer and nested members `stream->ctx->dc->current_state` without checking for NULL. All callers of these functions, such as in `dcn30_apply_idle_power_optimizations()` and `amdgpu_dm_plane_handle_cursor_update()`, already perform NULL checks before calling these functions. Fixes below: drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:336 dc_stream_program_cursor_attributes() error: we previously assumed 'stream' could be null (see line 334) drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c 327 bool dc_stream_program_cursor_attributes( 328 struct dc_stream_state *stream, 329 const struct dc_cursor_attributes *attributes) 330 { 331 struct dc *dc; 332 bool reset_idle_optimizations = false; 333 334 dc = stream ? stream->ctx->dc : NULL; ^^^^^^ The old code assumed stream could be NULL. 335 --> 336 if (dc_stream_set_cursor_attributes(stream, attributes)) { ^^^^^^ The refactor added an unchecked dereference. drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c 313 bool dc_stream_set_cursor_attributes( 314 struct dc_stream_state *stream, 315 const struct dc_cursor_attributes *attributes) 316 { 317 bool result = false; 318 319 if (dc_stream_check_cursor_attributes(stream, stream->ctx->dc->current_state, attributes)) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Here. This function used to check for if stream as NULL and return false at the start. Probably we should add that back.
CVE-2025-40183 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix metadata_dst leak __bpf_redirect_neigh_v{4,6} Cilium has a BPF egress gateway feature which forces outgoing K8s Pod traffic to pass through dedicated egress gateways which then SNAT the traffic in order to interact with stable IPs outside the cluster. The traffic is directed to the gateway via vxlan tunnel in collect md mode. A recent BPF change utilized the bpf_redirect_neigh() helper to forward packets after the arrival and decap on vxlan, which turned out over time that the kmalloc-256 slab usage in kernel was ever-increasing. The issue was that vxlan allocates the metadata_dst object and attaches it through a fake dst entry to the skb. The latter was never released though given bpf_redirect_neigh() was merely setting the new dst entry via skb_dst_set() without dropping an existing one first.
CVE-2025-40199 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: page_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches Helge reported that the introduction of PP_MAGIC_MASK let to crashes on boot on his 32-bit parisc machine. The cause of this is the mask is set too wide, so the page_pool_page_is_pp() incurs false positives which crashes the machine. Just disabling the check in page_pool_is_pp() will lead to the page_pool code itself malfunctioning; so instead of doing this, this patch changes the define for PP_DMA_INDEX_BITS to avoid mistaking arbitrary kernel pointers for page_pool-tagged pages. The fix relies on the kernel pointers that alias with the pp_magic field always being above PAGE_OFFSET. With this assumption, we can use the lowest bit of the value of PAGE_OFFSET as the upper bound of the PP_DMA_INDEX_MASK, which should avoid the false positives. Because we cannot rely on PAGE_OFFSET always being a compile-time constant, nor on it always being >0, we fall back to disabling the dma_index storage when there are not enough bits available. This leaves us in the situation we were in before the patch in the Fixes tag, but only on a subset of architecture configurations. This seems to be the best we can do until the transition to page types in complete for page_pool pages. v2: - Make sure there's at least 8 bits available and that the PAGE_OFFSET bit calculation doesn't wrap
CVE-2025-40214 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: af_unix: Initialise scc_index in unix_add_edge(). Quang Le reported that the AF_UNIX GC could garbage-collect a receive queue of an alive in-flight socket, with a nice repro. The repro consists of three stages. 1) 1-a. Create a single cyclic reference with many sockets 1-b. close() all sockets 1-c. Trigger GC 2) 2-a. Pass sk-A to an embryo sk-B 2-b. Pass sk-X to sk-X 2-c. Trigger GC 3) 3-a. accept() the embryo sk-B 3-b. Pass sk-B to sk-C 3-c. close() the in-flight sk-A 3-d. Trigger GC As of 2-c, sk-A and sk-X are linked to unix_unvisited_vertices, and unix_walk_scc() groups them into two different SCCs: unix_sk(sk-A)->vertex->scc_index = 2 (UNIX_VERTEX_INDEX_START) unix_sk(sk-X)->vertex->scc_index = 3 Once GC completes, unix_graph_grouped is set to true. Also, unix_graph_maybe_cyclic is set to true due to sk-X's cyclic self-reference, which makes close() trigger GC. At 3-b, unix_add_edge() allocates unix_sk(sk-B)->vertex and links it to unix_unvisited_vertices. unix_update_graph() is called at 3-a. and 3-b., but neither unix_graph_grouped nor unix_graph_maybe_cyclic is changed because both sk-B's listener and sk-C are not in-flight. 3-c decrements sk-A's file refcnt to 1. Since unix_graph_grouped is true at 3-d, unix_walk_scc_fast() is finally called and iterates 3 sockets sk-A, sk-B, and sk-X: sk-A -> sk-B (-> sk-C) sk-X -> sk-X This is totally fine. All of them are not yet close()d and should be grouped into different SCCs. However, unix_vertex_dead() misjudges that sk-A and sk-B are in the same SCC and sk-A is dead. unix_sk(sk-A)->scc_index == unix_sk(sk-B)->scc_index <-- Wrong! && sk-A's file refcnt == unix_sk(sk-A)->vertex->out_degree ^-- 1 in-flight count for sk-B -> sk-A is dead !? The problem is that unix_add_edge() does not initialise scc_index. Stage 1) is used for heap spraying, making a newly allocated vertex have vertex->scc_index == 2 (UNIX_VERTEX_INDEX_START) set by unix_walk_scc() at 1-c. Let's track the max SCC index from the previous unix_walk_scc() call and assign the max + 1 to a new vertex's scc_index. This way, we can continue to avoid Tarjan's algorithm while preventing misjudgments.
CVE-2025-40215 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: xfrm: delete x->tunnel as we delete x The ipcomp fallback tunnels currently get deleted (from the various lists and hashtables) as the last user state that needed that fallback is destroyed (not deleted). If a reference to that user state still exists, the fallback state will remain on the hashtables/lists, triggering the WARN in xfrm_state_fini. Because of those remaining references, the fix in commit f75a2804da39 ("xfrm: destroy xfrm_state synchronously on net exit path") is not complete. We recently fixed one such situation in TCP due to defered freeing of skbs (commit 9b6412e6979f ("tcp: drop secpath at the same time as we currently drop dst")). This can also happen due to IP reassembly: skbs with a secpath remain on the reassembly queue until netns destruction. If we can't guarantee that the queues are flushed by the time xfrm_state_fini runs, there may still be references to a (user) xfrm_state, preventing the timely deletion of the corresponding fallback state. Instead of chasing each instance of skbs holding a secpath one by one, this patch fixes the issue directly within xfrm, by deleting the fallback state as soon as the last user state depending on it has been deleted. Destruction will still happen when the final reference is dropped. A separate lockdep class for the fallback state is required since we're going to lock x->tunnel while x is locked.
CVE-2025-40218 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: mm/damon/vaddr: do not repeat pte_offset_map_lock() until success DAMON's virtual address space operation set implementation (vaddr) calls pte_offset_map_lock() inside the page table walk callback function. This is for reading and writing page table accessed bits. If pte_offset_map_lock() fails, it retries by returning the page table walk callback function with ACTION_AGAIN. pte_offset_map_lock() can continuously fail if the target is a pmd migration entry, though. Hence it could cause an infinite page table walk if the migration cannot be done until the page table walk is finished. This indeed caused a soft lockup when CPU hotplugging and DAMON were running in parallel. Avoid the infinite loop by simply not retrying the page table walk. DAMON is promising only a best-effort accuracy, so missing access to such pages is no problem.