syzbot has found a reproducer for the following issue on: HEAD commit: 610a9b8f49fb Linux 6.7-rc8 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=101fdde9e80000 kernel config: https://syzkaller.appspot.com/x/.config?x=c1d9baf5d2241e14 dashboard link: https://syzkaller.appspot.com/bug?extid=b18872ea9631b5dcef3b compiler: arm-linux-gnueabi-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 userspace arch: arm syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17a75c19e80000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1507d95ee80000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/8ead8862021c/non_bootable_disk-610a9b8f.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/5dcc5fecebbd/vmlinux-610a9b8f.xz kernel image: https://storage.googleapis.com/syzbot-assets/ac6cb620d377/zImage-610a9b8f.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+b18872ea9631b5dcef3b@xxxxxxxxxxxxxxxxxxxxxxxxx 8<--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 00000000 when read [00000000] *pgd=843b7003, *pmd=fe1bc003 Internal error: Oops: 207 [#1] PREEMPT SMP ARM Modules linked in: CPU: 0 PID: 2985 Comm: syz-executor305 Not tainted 6.7.0-rc8-syzkaller #0 Hardware name: ARM-Versatile Express PC is at page_zonenum include/linux/mmzone.h:1109 [inline] PC is at __kmap_local_page_prot+0xc/0x74 mm/highmem.c:573 LR is at kmap_local_page include/linux/highmem-internal.h:73 [inline] LR is at copy_page_to_iter+0xf8/0x184 lib/iov_iter.c:379 pc : [<8046aab0>] lr : [<807e0b68>] psr: 60000013 sp : df959c20 ip : df959c30 fp : df959c2c r10: 00000018 r9 : 828574e8 r8 : 00000000 r7 : 00000000 r6 : 00000000 r5 : 00000000 r4 : 8455ec00 r3 : 00c00000 r2 : 0000071f r1 : 00000000 r0 : 00000000 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 30c5387d Table: 8433f6c0 DAC: fffffffd Register r0 information: NULL pointer Register r1 information: NULL pointer Register r2 information: non-paged memory Register r3 information: non-paged memory Register r4 information: slab kmalloc-1k start 8455ec00 pointer offset 0 size 1024 Register r5 information: NULL pointer Register r6 information: NULL pointer Register r7 information: NULL pointer Register r8 information: NULL pointer Register r9 information: non-slab/vmalloc memory Register r10 information: non-paged memory Register r11 information: 2-page vmalloc region starting at 0xdf958000 allocated at kernel_clone+0xac/0x41c kernel/fork.c:2907 Register r12 information: 2-page vmalloc region starting at 0xdf958000 allocated at kernel_clone+0xac/0x41c kernel/fork.c:2907 Process syz-executor305 (pid: 2985, stack limit = 0xdf958000) Stack: (0xdf959c20 to 0xdf95a000) 9c20: df959c64 df959c30 807e0b68 8046aab0 df959c54 df959ef0 8024c5d8 8455ec00 9c40: 8455ec00 00000000 00000000 00000000 00000041 00000018 df959cb4 df959c68 9c60: 813da83c 807e0a7c 00000000 8423cd40 83a75600 83a756d0 83eaf300 83a756d8 9c80: df959ef0 00000000 806d5054 83eaf300 00000041 83a75600 82e96000 00000000 9ca0: 00000000 00000000 df959d24 df959cb8 815f77dc 813da758 00000000 df959ee0 9cc0: 00000000 00000000 00000000 00000000 83eaf3a8 83a756ec 83eaf53c df959ee0 9ce0: df959ee0 830a6780 00000000 00000000 00000000 97d26d6f df959d24 815f768c 9d00: 830a6780 20000d60 815f6ae4 00000000 00000000 df959d54 df959d44 df959d28 9d20: 815f6b1c 815f7698 00000000 830a6780 20000d40 df959ee0 df959e04 df959d48 9d40: 8134fd4c 815f6af0 00000000 00000000 00000001 00000000 00000000 00000000 9d60: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9d80: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9da0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9dc0: 00000000 00000000 00000000 00000000 00000000 97d26d6f 00000000 00000000 9de0: df959ee0 20000d60 00000000 830a6780 82e96000 00000002 df959e84 df959e08 9e00: 81352bdc 8134fc24 00000000 00000001 00000000 00000000 00000000 20000500 9e20: 00000041 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9e40: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 97d26d6f 9e60: df959e84 df959ec0 20000d60 00000001 00000000 00000000 df959f5c df959e88 9e80: 81352d04 81352b60 00000001 df959e98 8089202c 830a6780 00000000 00000000 9ea0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9ec0: 00000000 00000000 0002eb00 00000000 00000000 00000000 2f2e0001 656c6966 9ee0: df959d54 00000000 00000000 00000000 00000000 00000000 20000500 00000041 9f00: 00000001 00000000 00000000 00000001 00000000 00000000 00000000 00000000 9f20: 00000000 00000000 00000176 97d26d6f 82e96000 00000003 20000d40 00000000 9f40: 00000000 00000002 82e96000 0000016d df959fa4 df959f60 813536d4 81352c1c 9f60: 00000000 ffffffff 00000000 00000000 00000000 00000000 82e96000 97d26d6f 9f80: df959fa4 00000000 00000000 0008e060 0000016d 80200288 00000000 df959fa8 9fa0: 80200060 8135361c 00000000 00000000 00000003 20000d40 00000002 00000000 9fc0: 00000000 00000000 0008e060 0000016d 0007107c 00000000 00000001 20000100 9fe0: 7ebf3c70 7ebf3c60 0001094c 0002eb00 00000010 00000003 00000000 00000000 Backtrace: [<8046aaa4>] (__kmap_local_page_prot) from [<807e0b68>] (kmap_local_page include/linux/highmem-internal.h:73 [inline]) [<8046aaa4>] (__kmap_local_page_prot) from [<807e0b68>] (copy_page_to_iter+0xf8/0x184 lib/iov_iter.c:379) [<807e0a70>] (copy_page_to_iter) from [<813da83c>] (sk_msg_recvmsg+0xf0/0x3cc net/core/skmsg.c:437) r10:00000018 r9:00000041 r8:00000000 r7:00000000 r6:00000000 r5:8455ec00 r4:8455ec00 [<813da74c>] (sk_msg_recvmsg) from [<815f77dc>] (unix_bpf_recvmsg net/unix/unix_bpf.c:73 [inline]) [<813da74c>] (sk_msg_recvmsg) from [<815f77dc>] (unix_bpf_recvmsg+0x150/0x444 net/unix/unix_bpf.c:50) r10:00000000 r9:00000000 r8:00000000 r7:82e96000 r6:83a75600 r5:00000041 r4:83eaf300 [<815f768c>] (unix_bpf_recvmsg) from [<815f6b1c>] (unix_dgram_recvmsg+0x38/0x4c net/unix/af_unix.c:2483) r10:df959d54 r9:00000000 r8:00000000 r7:815f6ae4 r6:20000d60 r5:830a6780 r4:815f768c [<815f6ae4>] (unix_dgram_recvmsg) from [<8134fd4c>] (sock_recvmsg_nosec net/socket.c:1044 [inline]) [<815f6ae4>] (unix_dgram_recvmsg) from [<8134fd4c>] (____sys_recvmsg+0x134/0x158 net/socket.c:2801) r4:df959ee0 [<8134fc18>] (____sys_recvmsg) from [<81352bdc>] (___sys_recvmsg+0x88/0xbc net/socket.c:2845) r10:00000002 r9:82e96000 r8:830a6780 r7:00000000 r6:20000d60 r5:df959ee0 r4:00000000 [<81352b54>] (___sys_recvmsg) from [<81352d04>] (do_recvmmsg+0xf4/0x298 net/socket.c:2939) r8:00000000 r7:00000000 r6:00000001 r5:20000d60 r4:df959ec0 [<81352c10>] (do_recvmmsg) from [<813536d4>] (__sys_recvmmsg net/socket.c:3018 [inline]) [<81352c10>] (do_recvmmsg) from [<813536d4>] (__do_sys_recvmmsg_time32 net/socket.c:3052 [inline]) [<81352c10>] (do_recvmmsg) from [<813536d4>] (sys_recvmmsg_time32+0xc4/0xd8 net/socket.c:3045) r10:0000016d r9:82e96000 r8:00000002 r7:00000000 r6:00000000 r5:20000d40 r4:00000003 [<81353610>] (sys_recvmmsg_time32) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:66) Exception stack(0xdf959fa8 to 0xdf959ff0) 9fa0: 00000000 00000000 00000003 20000d40 00000002 00000000 9fc0: 00000000 00000000 0008e060 0000016d 0007107c 00000000 00000001 20000100 9fe0: 7ebf3c70 7ebf3c60 0001094c 0002eb00 r8:80200288 r7:0000016d r6:0008e060 r5:00000000 r4:00000000 Code: eaffffe8 e1a0c00d e92dd800 e24cb004 (e5901000) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: eaffffe8 b 0xffffffa8 4: e1a0c00d mov ip, sp 8: e92dd800 push {fp, ip, lr, pc} c: e24cb004 sub fp, ip, #4 * 10: e5901000 ldr r1, [r0] <-- trapping instruction --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.
