8<--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 0000000e when read [0000000e] *pgd=80000080004003, *pmd=00000000 Internal error: Oops: 207 [#1] PREEMPT SMP ARM Modules linked in: CPU: 0 PID: 20796 Comm: kworker/u4:0 Not tainted 6.4.0-rc3-syzkaller #0 Hardware name: ARM-Versatile Express Workqueue: events_unbound io_ring_exit_work PC is at __io_remove_buffers io_uring/kbuf.c:219 [inline] PC is at __io_remove_buffers+0x38/0x184 io_uring/kbuf.c:209 LR is at io_destroy_buffers+0x40/0x134 io_uring/kbuf.c:268 pc : [<807aeeb8>] lr : [<807af454>] psr: 20000113 sp : dfb61e48 ip : dfb61e78 fp : dfb61e74 r10: 87f58c28 r9 : 87f58800 r8 : ffffffff r7 : 87f58ba8 r6 : 00000001 r5 : 87f5d000 r4 : 00000000 r3 : 00000000 r2 : 00000000 r1 : 87f5d000 r0 : 87f58800 Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 30c5387d Table: 85a92340 DAC: fffffffd Register r0 information: slab kmalloc-2k start 87f58800 pointer offset 0 size 2048 Register r1 information: slab kmalloc-2k start 87f5d000 pointer offset 0 size 2048 Register r2 information: NULL pointer Register r3 information: NULL pointer Register r4 information: NULL pointer Register r5 information: slab kmalloc-2k start 87f5d000 pointer offset 0 size 2048 Register r6 information: non-paged memory Register r7 information: slab kmalloc-2k start 87f58800 pointer offset 936 size 2048 Register r8 information: non-paged memory Register r9 information: slab kmalloc-2k start 87f58800 pointer offset 0 size 2048 Register r10 information: slab kmalloc-2k start 87f58800 pointer offset 1064 size 2048 Register r11 information: 2-page vmalloc region starting at 0xdfb60000 allocated at kernel_clone+0x9c/0x3dc kernel/fork.c:2918 Register r12 information: 2-page vmalloc region starting at 0xdfb60000 allocated at kernel_clone+0x9c/0x3dc kernel/fork.c:2918 Process kworker/u4:0 (pid: 20796, stack limit = 0xdfb60000) Stack: (0xdfb61e48 to 0xdfb62000) 1e40: 00000000 00000014 87f58800 87f58840 87f58ba8 81fe84f0 1e60: 00000005 87f58c28 dfb61e9c dfb61e78 807af454 807aee8c dfb61e74 9747b37e 1e80: 87f58c18 87f58800 87f58840 87f58ba8 dfb61efc dfb61ea0 817e0e38 807af420 1ea0: 81fe84f0 82604d40 00068ed8 87f58808 807d5fe4 817dfb8c 00000000 00000000 1ec0: dfb61ec0 dfb61ec0 87f58800 9747b37e 80264210 87f58c18 85fed600 8300e800 1ee0: 83016000 00000100 83289780 83016005 dfb61f44 dfb61f00 8026399c 817e0a9c 1f00: 80277dd0 802a6080 dfb61f2c dfb61f18 80264614 00000000 8300e800 85fed600 1f20: 8300e800 85fed618 8300e820 82604d40 00000088 8300e800 dfb61f84 dfb61f48 1f40: 80264190 8026379c dfb61f64 81f8f604 827e1633 83289780 dfb61f84 860514c0 1f60: 83289780 80264124 85fed600 86051b80 dfc75e9c 00000000 dfb61fac dfb61f88 1f80: 8026b19c 80264130 860514c0 8026b09c 00000000 00000000 00000000 00000000 1fa0: 00000000 dfb61fb0 80200100 8026b0a8 00000000 00000000 00000000 00000000 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000 Backtrace: [<807aee80>] (__io_remove_buffers) from [<807af454>] (io_destroy_buffers+0x40/0x134 io_uring/kbuf.c:268) r10:87f58c28 r9:00000005 r8:81fe84f0 r7:87f58ba8 r6:87f58840 r5:87f58800 r4:00000014 r3:00000000 [<807af414>] (io_destroy_buffers) from [<817e0e38>] (io_ring_ctx_free io_uring/io_uring.c:2846 [inline]) [<807af414>] (io_destroy_buffers) from [<817e0e38>] (io_ring_exit_work+0x3a8/0x600 io_uring/io_uring.c:3088) r7:87f58ba8 r6:87f58840 r5:87f58800 r4:87f58c18 [<817e0a90>] (io_ring_exit_work) from [<8026399c>] (process_one_work+0x20c/0x598 kernel/workqueue.c:2405) r10:83016005 r9:83289780 r8:00000100 r7:83016000 r6:8300e800 r5:85fed600 r4:87f58c18 [<80263790>] (process_one_work) from [<80264190>] (worker_thread+0x6c/0x4e0 kernel/workqueue.c:2552) r10:8300e800 r9:00000088 r8:82604d40 r7:8300e820 r6:85fed618 r5:8300e800 r4:85fed600 [<80264124>] (worker_thread) from [<8026b19c>] (kthread+0x100/0x130 kernel/kthread.c:379) r10:00000000 r9:dfc75e9c r8:86051b80 r7:85fed600 r6:80264124 r5:83289780 r4:860514c0 [<8026b09c>] (kthread) from [<80200100>] (ret_from_fork+0x14/0x34 arch/arm/kernel/entry-common.S:133) Exception stack(0xdfb61fb0 to 0xdfb61ff8) 1fa0: 00000000 00000000 00000000 00000000 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:8026b09c r4:860514c0 Code: 0a000022 e5913004 e1d120be e5d14013 (e1d380be) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: 0a000022 beq 0x90 4: e5913004 ldr r3, [r1, #4] 8: e1d120be ldrh r2, [r1, #14] c: e5d14013 ldrb r4, [r1, #19] * 10: e1d380be ldrh r8, [r3, #14] <-- trapping instruction