syzbot


BUG: unable to handle kernel NULL pointer dereference in p9_client_prepare_req

Status: moderation: reported on 2025/04/10 21:16
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+4d7f9da8c09dfad36210@syzkaller.appspotmail.com
First crash: 8d11h, last: 8d11h
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: unable to handle kernel paging request in p9_client_prepare_req v9fs C 1 880d 880d 0/28 auto-obsoleted due to no activity on 2023/03/16 19:40

Sample crash report:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000011

======================================================
WARNING: possible circular locking dependency detected
6.14.0-syzkaller-gd6b13dbd03b7 #0 Not tainted
------------------------------------------------------
syz-executor/6477 is trying to acquire lock:
ffff80008fe0f3e0 (console_owner){....}-{0:0}, at: console_lock_spinning_enable+0x88/0xec kernel/printk/printk.c:1920

but task is already holding lock:
fffffdffbf704200 (&c->lock){-.-.}-{3:3}, at: local_lock_acquire+0x4/0x98 include/linux/local_lock_internal.h:28

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&c->lock){-.-.}-{3:3}:
       local_lock_acquire+0x3c/0x98 include/linux/local_lock_internal.h:29
       ___slab_alloc+0x2cc/0xf4c mm/slub.c:3703
       __slab_alloc+0x74/0xd0 mm/slub.c:3916
       __slab_alloc_node mm/slub.c:3991 [inline]
       slab_alloc_node mm/slub.c:4152 [inline]
       kmem_cache_alloc_noprof+0x300/0x410 mm/slub.c:4171
       kmem_alloc_batch lib/debugobjects.c:371 [inline]
       fill_pool+0x234/0x5e8 lib/debugobjects.c:403
       debug_objects_fill_pool+0x84/0xa0 lib/debugobjects.c:725
       debug_object_activate+0x48/0x4ac lib/debugobjects.c:814
       debug_work_activate kernel/workqueue.c:664 [inline]
       insert_work+0x4c/0x2d4 kernel/workqueue.c:2180
       __queue_work+0xe34/0x1324 kernel/workqueue.c:2341
       queue_work_on+0xe0/0x1a0 kernel/workqueue.c:2392
       queue_work include/linux/workqueue.h:662 [inline]
       call_usermodehelper_exec+0x238/0x48c kernel/umh.c:433
       kobject_uevent_env+0x648/0x894 lib/kobject_uevent.c:632
       kobject_uevent+0x2c/0x3c lib/kobject_uevent.c:656
       device_add+0x54c/0xa6c drivers/base/core.c:3647
       device_register+0x28/0x38 drivers/base/core.c:3748
       init_clocksource_sysfs+0x50/0x68 kernel/time/clocksource.c:1494
       do_one_initcall+0x254/0xaa4 init/main.c:1257
       do_initcall_level+0x154/0x214 init/main.c:1319
       do_initcalls+0x84/0xf4 init/main.c:1335
       do_basic_setup+0x8c/0xa0 init/main.c:1354
       kernel_init_freeable+0x324/0x478 init/main.c:1568
       kernel_init+0x24/0x2a0 init/main.c:1457
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862

-> #3 (&pool->lock){-.-.}-{2:2}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154
       __queue_work+0x8d4/0x1324 kernel/workqueue.c:-1
       queue_work_on+0xe0/0x1a0 kernel/workqueue.c:2392
       queue_work include/linux/workqueue.h:662 [inline]
       rpm_suspend+0xc1c/0x1444 drivers/base/power/runtime.c:662
       rpm_idle+0x570/0x8c0 drivers/base/power/runtime.c:536
       __pm_runtime_idle+0x114/0x1d4 drivers/base/power/runtime.c:1104
       pm_runtime_put include/linux/pm_runtime.h:448 [inline]
       __device_attach+0x34c/0x434 drivers/base/dd.c:1048
       device_initial_probe+0x24/0x34 drivers/base/dd.c:1079
       bus_probe_device+0x178/0x240 drivers/base/bus.c:537
       device_add+0x728/0xa6c drivers/base/core.c:3666
       serial_base_port_add+0x25c/0x370 drivers/tty/serial/serial_base_bus.c:179
       serial_core_port_device_add drivers/tty/serial/serial_core.c:3344 [inline]
       serial_core_register_port+0x300/0x2118 drivers/tty/serial/serial_core.c:3383
       serial_ctrl_register_port+0x28/0x38 drivers/tty/serial/serial_ctrl.c:41
       uart_add_one_port+0x28/0x38 drivers/tty/serial/serial_port.c:143
       pl011_register_port+0x1b4/0x44c drivers/tty/serial/amba-pl011.c:2812
       sbsa_uart_probe+0x488/0x608 drivers/tty/serial/amba-pl011.c:2987
       platform_probe+0x148/0x1c0 drivers/base/platform.c:1404
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x38c/0x8fc drivers/base/dd.c:658
       __driver_probe_device+0x194/0x374 drivers/base/dd.c:800
       driver_probe_device+0x78/0x330 drivers/base/dd.c:830
       __device_attach_driver+0x2a8/0x4f4 drivers/base/dd.c:958
       bus_for_each_drv+0x228/0x2bc drivers/base/bus.c:462
       __device_attach+0x2b4/0x434 drivers/base/dd.c:1030
       device_initial_probe+0x24/0x34 drivers/base/dd.c:1079
       bus_probe_device+0x178/0x240 drivers/base/bus.c:537
       device_add+0x728/0xa6c drivers/base/core.c:3666
       platform_device_add+0x3e8/0x6e8 drivers/base/platform.c:716
       platform_device_register_full+0x3c4/0x4bc drivers/base/platform.c:844
       acpi_create_platform_device+0x5e4/0x76c drivers/acpi/acpi_platform.c:177
       acpi_default_enumeration+0x6c/0xdc drivers/acpi/scan.c:2212
       acpi_bus_attach+0x8b8/0xaa8 drivers/acpi/scan.c:2323
       acpi_dev_for_one_check+0xa0/0xb4 drivers/acpi/bus.c:1145
       device_for_each_child+0xf0/0x180 drivers/base/core.c:3995
       acpi_dev_for_each_child+0xc4/0x108 drivers/acpi/bus.c:1157
       acpi_bus_attach+0x358/0xaa8 drivers/acpi/scan.c:2328
       acpi_dev_for_one_check+0xa0/0xb4 drivers/acpi/bus.c:1145
       device_for_each_child+0xf0/0x180 drivers/base/core.c:3995
       acpi_dev_for_each_child+0xc4/0x108 drivers/acpi/bus.c:1157
       acpi_bus_attach+0x358/0xaa8 drivers/acpi/scan.c:2328
       acpi_bus_scan+0x118/0x4f0 drivers/acpi/scan.c:2609
       acpi_scan_init+0x214/0x6b0 drivers/acpi/scan.c:2746
       acpi_init+0x190/0x250 drivers/acpi/bus.c:1467
       do_one_initcall+0x254/0xaa4 init/main.c:1257
       do_initcall_level+0x154/0x214 init/main.c:1319
       do_initcalls+0x84/0xf4 init/main.c:1335
       do_basic_setup+0x8c/0xa0 init/main.c:1354
       kernel_init_freeable+0x324/0x478 init/main.c:1568
       kernel_init+0x24/0x2a0 init/main.c:1457
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862

-> #2 (&dev->power.lock){-...}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162
       __pm_runtime_resume+0xf0/0x180 drivers/base/power/runtime.c:1171
       pm_runtime_get include/linux/pm_runtime.h:396 [inline]
       __uart_start+0x154/0x3d8 drivers/tty/serial/serial_core.c:148
       uart_write+0x270/0x9b4 drivers/tty/serial/serial_core.c:635
       process_output_block drivers/tty/n_tty.c:574 [inline]
       n_tty_write+0xaec/0xed0 drivers/tty/n_tty.c:2389
       iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
       file_tty_write+0x410/0x7b8 drivers/tty/tty_io.c:1090
       tty_write drivers/tty/tty_io.c:1111 [inline]
       redirected_tty_write+0xa8/0x144 drivers/tty/tty_io.c:1134
       new_sync_write fs/read_write.c:586 [inline]
       vfs_write+0x704/0xa9c fs/read_write.c:679
       ksys_write+0x15c/0x26c fs/read_write.c:731
       __do_sys_write fs/read_write.c:742 [inline]
       __se_sys_write fs/read_write.c:739 [inline]
       __arm64_sys_write+0x7c/0x90 fs/read_write.c:739
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
       el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
       el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

-> #1 (&port_lock_key){....}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162
       uart_port_lock_irqsave include/linux/serial_core.h:715 [inline]
       pl011_console_write+0x158/0xdc0 drivers/tty/serial/amba-pl011.c:2384
       console_emit_next_record kernel/printk/printk.c:3122 [inline]
       console_flush_all+0x604/0xb90 kernel/printk/printk.c:3210
       __console_flush_and_unlock kernel/printk/printk.c:3269 [inline]
       console_unlock+0x138/0x3ac kernel/printk/printk.c:3309
       vprintk_emit+0x308/0x55c kernel/printk/printk.c:2432
       vprintk_default+0xa0/0xe4 kernel/printk/printk.c:2447
       vprintk+0x94/0x12c kernel/printk/printk_safe.c:82
       _printk+0xdc/0x128 kernel/printk/printk.c:2457
       register_console+0x8f0/0xcc0 kernel/printk/printk.c:4099
       uart_configure_port drivers/tty/serial/serial_core.c:2639 [inline]
       serial_core_add_one_port drivers/tty/serial/serial_core.c:3160 [inline]
       serial_core_register_port+0x1688/0x2118 drivers/tty/serial/serial_core.c:3391
       serial_ctrl_register_port+0x28/0x38 drivers/tty/serial/serial_ctrl.c:41
       uart_add_one_port+0x28/0x38 drivers/tty/serial/serial_port.c:143
       pl011_register_port+0x1b4/0x44c drivers/tty/serial/amba-pl011.c:2812
       sbsa_uart_probe+0x488/0x608 drivers/tty/serial/amba-pl011.c:2987
       platform_probe+0x148/0x1c0 drivers/base/platform.c:1404
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x38c/0x8fc drivers/base/dd.c:658
       __driver_probe_device+0x194/0x374 drivers/base/dd.c:800
       driver_probe_device+0x78/0x330 drivers/base/dd.c:830
       __device_attach_driver+0x2a8/0x4f4 drivers/base/dd.c:958
       bus_for_each_drv+0x228/0x2bc drivers/base/bus.c:462
       __device_attach+0x2b4/0x434 drivers/base/dd.c:1030
       device_initial_probe+0x24/0x34 drivers/base/dd.c:1079
       bus_probe_device+0x178/0x240 drivers/base/bus.c:537
       device_add+0x728/0xa6c drivers/base/core.c:3666
       platform_device_add+0x3e8/0x6e8 drivers/base/platform.c:716
       platform_device_register_full+0x3c4/0x4bc drivers/base/platform.c:844
       acpi_create_platform_device+0x5e4/0x76c drivers/acpi/acpi_platform.c:177
       acpi_default_enumeration+0x6c/0xdc drivers/acpi/scan.c:2212
       acpi_bus_attach+0x8b8/0xaa8 drivers/acpi/scan.c:2323
       acpi_dev_for_one_check+0xa0/0xb4 drivers/acpi/bus.c:1145
       device_for_each_child+0xf0/0x180 drivers/base/core.c:3995
       acpi_dev_for_each_child+0xc4/0x108 drivers/acpi/bus.c:1157
       acpi_bus_attach+0x358/0xaa8 drivers/acpi/scan.c:2328
       acpi_dev_for_one_check+0xa0/0xb4 drivers/acpi/bus.c:1145
       device_for_each_child+0xf0/0x180 drivers/base/core.c:3995
       acpi_dev_for_each_child+0xc4/0x108 drivers/acpi/bus.c:1157
       acpi_bus_attach+0x358/0xaa8 drivers/acpi/scan.c:2328
       acpi_bus_scan+0x118/0x4f0 drivers/acpi/scan.c:2609
       acpi_scan_init+0x214/0x6b0 drivers/acpi/scan.c:2746
       acpi_init+0x190/0x250 drivers/acpi/bus.c:1467
       do_one_initcall+0x254/0xaa4 init/main.c:1257
       do_initcall_level+0x154/0x214 init/main.c:1319
       do_initcalls+0x84/0xf4 init/main.c:1335
       do_basic_setup+0x8c/0xa0 init/main.c:1354
       kernel_init_freeable+0x324/0x478 init/main.c:1568
       kernel_init+0x24/0x2a0 init/main.c:1457
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862

-> #0 (console_owner){....}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain kernel/locking/lockdep.c:3906 [inline]
       __lock_acquire+0x34f0/0x7904 kernel/locking/lockdep.c:5228
       lock_acquire+0x23c/0x724 kernel/locking/lockdep.c:5851
       console_lock_spinning_enable+0xb4/0xec kernel/printk/printk.c:1924
       console_emit_next_record kernel/printk/printk.c:3116 [inline]
       console_flush_all+0x5c4/0xb90 kernel/printk/printk.c:3210
       __console_flush_and_unlock kernel/printk/printk.c:3269 [inline]
       console_unlock+0x138/0x3ac kernel/printk/printk.c:3309
       vprintk_emit+0x308/0x55c kernel/printk/printk.c:2432
       vprintk_default+0xa0/0xe4 kernel/printk/printk.c:2447
       vprintk+0x94/0x12c kernel/printk/printk_safe.c:82
       _printk+0xdc/0x128 kernel/printk/printk.c:2457
       die_kernel_fault arch/arm64/mm/fault.c:310 [inline]
       __do_kernel_fault+0x4cc/0x528 arch/arm64/mm/fault.c:411
       do_page_fault+0x15c/0x10ac arch/arm64/mm/fault.c:772
       do_translation_fault+0xc4/0x114 arch/arm64/mm/fault.c:783
       do_mem_abort+0x74/0x200 arch/arm64/mm/fault.c:919
       el1_abort+0x3c/0x5c arch/arm64/kernel/entry-common.c:432
       el1h_64_sync_handler+0x60/0xcc arch/arm64/kernel/entry-common.c:510
       el1h_64_sync+0x6c/0x70 arch/arm64/kernel/entry.S:595
       ___slab_alloc+0x1a8/0xf4c mm/slub.c:3762
       __slab_alloc+0x74/0xd0 mm/slub.c:3916
       __slab_alloc_node mm/slub.c:3991 [inline]
       slab_alloc_node mm/slub.c:4152 [inline]
       kmem_cache_alloc_noprof+0x300/0x410 mm/slub.c:4171
       p9_fcall_init net/9p/client.c:230 [inline]
       p9_tag_alloc net/9p/client.c:298 [inline]
       p9_client_prepare_req+0x300/0xf10 net/9p/client.c:644
       p9_client_rpc+0x170/0x99c net/9p/client.c:691
       p9_client_clunk+0x7c/0x214 net/9p/client.c:1451
       p9_fid_put include/net/9p/client.h:280 [inline]
       v9fs_dentry_release+0x18c/0x278 fs/9p/vfs_dentry.c:61
       __dentry_kill+0x27c/0x5e8 fs/dcache.c:648
       dput+0x1b8/0x290 fs/dcache.c:885
       do_one_tree+0xc8/0xfc fs/dcache.c:1581
       shrink_dcache_for_umount+0xd8/0x188 fs/dcache.c:1595
       generic_shutdown_super+0x68/0x2bc fs/super.c:620
       kill_anon_super+0x4c/0x7c fs/super.c:1237
       v9fs_kill_super+0x4c/0x90 fs/9p/vfs_super.c:193
       deactivate_locked_super+0xc4/0x12c fs/super.c:473
       deactivate_super+0xe0/0x100 fs/super.c:506
       cleanup_mnt+0x34c/0x3dc fs/namespace.c:1413
       __cleanup_mnt+0x20/0x30 fs/namespace.c:1420
       task_work_run+0x230/0x2e0 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       do_notify_resume+0x178/0x1f4 arch/arm64/kernel/entry-common.c:151
       exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
       exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
       el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:745
       el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

other info that might help us debug this:

Chain exists of:
  console_owner --> &pool->lock --> &c->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&c->lock);
                               lock(&pool->lock);
                               lock(&c->lock);
  lock(console_owner);

 *** DEADLOCK ***

4 locks held by syz-executor/6477:
 #0: ffff0000d64a00e0 (&type->s_umount_key#62){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff0000d64a00e0 (&type->s_umount_key#62){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff0000d64a00e0 (&type->s_umount_key#62){+.+.}-{4:4}, at: deactivate_super+0xd8/0x100 fs/super.c:505
 #1: fffffdffbf704200 (&c->lock){-.-.}-{3:3}, at: local_lock_acquire+0x4/0x98 include/linux/local_lock_internal.h:28
 #2: ffff80008fe0f440 (console_lock){+.+.}-{0:0}, at: vprintk_emit+0x2ec/0x55c kernel/printk/printk.c:2431
 #3: ffff80008fe0f050 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire+0x10/0x4c include/linux/rcupdate.h:341

stack backtrace:
CPU: 1 UID: 0 PID: 6477 Comm: syz-executor Not tainted 6.14.0-syzkaller-gd6b13dbd03b7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 print_circular_bug+0x154/0x1c0 kernel/locking/lockdep.c:2076
 check_noncircular+0x310/0x404 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain kernel/locking/lockdep.c:3906 [inline]
 __lock_acquire+0x34f0/0x7904 kernel/locking/lockdep.c:5228
 lock_acquire+0x23c/0x724 kernel/locking/lockdep.c:5851
 console_lock_spinning_enable+0xb4/0xec kernel/printk/printk.c:1924
 console_emit_next_record kernel/printk/printk.c:3116 [inline]
 console_flush_all+0x5c4/0xb90 kernel/printk/printk.c:3210
 __console_flush_and_unlock kernel/printk/printk.c:3269 [inline]
 console_unlock+0x138/0x3ac kernel/printk/printk.c:3309
 vprintk_emit+0x308/0x55c kernel/printk/printk.c:2432
 vprintk_default+0xa0/0xe4 kernel/printk/printk.c:2447
 vprintk+0x94/0x12c kernel/printk/printk_safe.c:82
 _printk+0xdc/0x128 kernel/printk/printk.c:2457
 die_kernel_fault arch/arm64/mm/fault.c:310 [inline]
 __do_kernel_fault+0x4cc/0x528 arch/arm64/mm/fault.c:411
 do_page_fault+0x15c/0x10ac arch/arm64/mm/fault.c:772
 do_translation_fault+0xc4/0x114 arch/arm64/mm/fault.c:783
 do_mem_abort+0x74/0x200 arch/arm64/mm/fault.c:919
 el1_abort+0x3c/0x5c arch/arm64/kernel/entry-common.c:432
 el1h_64_sync_handler+0x60/0xcc arch/arm64/kernel/entry-common.c:510
 el1h_64_sync+0x6c/0x70 arch/arm64/kernel/entry.S:595
 ___slab_alloc+0x1a8/0xf4c mm/slub.c:3762 (P)
 __slab_alloc+0x74/0xd0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 kmem_cache_alloc_noprof+0x300/0x410 mm/slub.c:4171
 p9_fcall_init net/9p/client.c:230 [inline]
 p9_tag_alloc net/9p/client.c:298 [inline]
 p9_client_prepare_req+0x300/0xf10 net/9p/client.c:644
 p9_client_rpc+0x170/0x99c net/9p/client.c:691
 p9_client_clunk+0x7c/0x214 net/9p/client.c:1451
 p9_fid_put include/net/9p/client.h:280 [inline]
 v9fs_dentry_release+0x18c/0x278 fs/9p/vfs_dentry.c:61
 __dentry_kill+0x27c/0x5e8 fs/dcache.c:648
 dput+0x1b8/0x290 fs/dcache.c:885
 do_one_tree+0xc8/0xfc fs/dcache.c:1581
 shrink_dcache_for_umount+0xd8/0x188 fs/dcache.c:1595
 generic_shutdown_super+0x68/0x2bc fs/super.c:620
 kill_anon_super+0x4c/0x7c fs/super.c:1237
 v9fs_kill_super+0x4c/0x90 fs/9p/vfs_super.c:193
 deactivate_locked_super+0xc4/0x12c fs/super.c:473
 deactivate_super+0xe0/0x100 fs/super.c:506
 cleanup_mnt+0x34c/0x3dc fs/namespace.c:1413
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1420
 task_work_run+0x230/0x2e0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 do_notify_resume+0x178/0x1f4 arch/arm64/kernel/entry-common.c:151
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:745
 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=000000012c5a1000
[0000000000000011] pgd=0800000114326403, p4d=0800000114326403, pud=0000000000000000
Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 UID: 0 PID: 6477 Comm: syz-executor Not tainted 6.14.0-syzkaller-gd6b13dbd03b7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ___slab_alloc+0x1a8/0xf4c mm/slub.c:3769
lr : ___slab_alloc+0x198/0xf4c mm/slub.c:3757
sp : ffff8000a44d7350
x29: ffff8000a44d73b0 x28: 0000000000001000 x27: 0000000000000c40
x26: ffff800097ab1688 x25: 00000000ffffffff x24: 0000000000000000
x23: 00007dfe9bc421e0 x22: ffff80008b3ff634 x21: 0000000000000001
x20: fffffdffbf7041e0 x19: ffff0000f4511c80 x18: ffff8000a44d6b40
x17: 0000000000026538 x16: ffff8000832bccd4 x15: 0000000000000004
x14: 1ffff00011faa0cd x13: dfff800000000000 x12: 000000000ba5de8b
x11: 000000007b366a5b x10: 0000000000000003 x9 : 38250c81e32bae00
x8 : 0000000000000000 x7 : ffff800080b5c3dc x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000001 x3 : ffff80008f2befd4
x2 : 0000000000000008 x1 : ffff80008b91b940 x0 : 0000000000000001
Call trace:
 ___slab_alloc+0x1a8/0xf4c mm/slub.c:3762 (P)
 __slab_alloc+0x74/0xd0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 kmem_cache_alloc_noprof+0x300/0x410 mm/slub.c:4171
 p9_fcall_init net/9p/client.c:230 [inline]
 p9_tag_alloc net/9p/client.c:298 [inline]
 p9_client_prepare_req+0x300/0xf10 net/9p/client.c:644
 p9_client_rpc+0x170/0x99c net/9p/client.c:691
 p9_client_clunk+0x7c/0x214 net/9p/client.c:1451
 p9_fid_put include/net/9p/client.h:280 [inline]
 v9fs_dentry_release+0x18c/0x278 fs/9p/vfs_dentry.c:61
 __dentry_kill+0x27c/0x5e8 fs/dcache.c:648
 dput+0x1b8/0x290 fs/dcache.c:885
 do_one_tree+0xc8/0xfc fs/dcache.c:1581
 shrink_dcache_for_umount+0xd8/0x188 fs/dcache.c:1595
 generic_shutdown_super+0x68/0x2bc fs/super.c:620
 kill_anon_super+0x4c/0x7c fs/super.c:1237
 v9fs_kill_super+0x4c/0x90 fs/9p/vfs_super.c:193
 deactivate_locked_super+0xc4/0x12c fs/super.c:473
 deactivate_super+0xe0/0x100 fs/super.c:506
 cleanup_mnt+0x34c/0x3dc fs/namespace.c:1413
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1420
 task_work_run+0x230/0x2e0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 do_notify_resume+0x178/0x1f4 arch/arm64/kernel/entry-common.c:151
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:745
 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Code: f9400a88 b50011e8 f9400e95 b40024b5 (f9400aa8) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	f9400a88 	ldr	x8, [x20, #16]
   4:	b50011e8 	cbnz	x8, 0x240
   8:	f9400e95 	ldr	x21, [x20, #24]
   c:	b40024b5 	cbz	x21, 0x4a0
* 10:	f9400aa8 	ldr	x8, [x21, #16] <-- trapping instruction

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/06 21:10 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci d6b13dbd03b7 1c65791e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel NULL pointer dereference in p9_client_prepare_req
* Struck through repros no longer work on HEAD.