Dear Linux Developer, Recently when using our tool to fuzz kernel, the following crash was triggered: HEAD commit: 64570fbc14f8 Linux 5.15-rc5 git tree: upstream compiler: gcc 8.0.1 console output: https://drive.google.com/file/d/1ec016fbMgmvittn6-wHxp8V_9adDCRrY/view?usp=share_link kernel config: https://drive.google.com/file/d/1uDOeEYgJDcLiSOrx9W8v2bqZ6uOA_55t/view?usp=share_link Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: Wei Chen <harperchen1110@xxxxxxxxx> loop0: detected capacity change from 0 to 61456 BUG: kernel NULL pointer dereference, address: 00000000000005d0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 107f59067 P4D 107f59067 PUD 109722067 PMD 0 Oops: 0000 [#1] PREEMPT SMP CPU: 1 PID: 17581 Comm: syz-executor.0 Not tainted 5.15.0-rc5 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014 RIP: 0010:bio_associate_blkg_from_css+0x331/0xb90 Code: fe 48 c7 c6 79 f7 54 82 48 c7 c7 e0 de 41 86 e8 75 04 db fe 48 8b 45 d0 49 89 46 48 e9 ec 00 00 00 e8 b3 7b e8 fe 49 8b 46 08 <48> 8b 80 d0 05 00 00 48 8b 80 90 00 00 00 4c 8b a0 f0 04 00 00 e8 RSP: 0018:ffffc90003de7b10 EFLAGS: 00010212 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc9000b9f1000 RSI: ffff88810b5f9b80 RDI: 0000000000000002 RBP: ffffc90003de7b60 R08: ffffffff8254f7ad R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000001 R12: ffffffff892f6f60 R13: ffff88810717fc00 R14: ffff888107d38700 R15: 0000000000000046 FS: 00007fc6ebc98700(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000005d0 CR3: 000000012f494000 CR4: 00000000003506e0 Call Trace: bio_associate_blkg+0x94/0x2c0 lbmStartIO+0xb6/0x160 lbmWrite+0x18b/0x210 lmNextPage+0xb6/0x1d0 lmWriteRecord+0x4ca/0x630 lmLog+0x1a3/0x3e0 jfs_mount_rw+0x1fb/0x230 jfs_fill_super+0x379/0x480 mount_bdev+0x23d/0x280 legacy_get_tree+0x2e/0x90 vfs_get_tree+0x29/0x100 path_mount+0x58e/0x10a0 do_mount+0x9b/0xb0 __x64_sys_mount+0x13a/0x150 do_syscall_64+0x34/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x46abda Code: 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc6ebc97a48 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fc6ebc97af0 RCX: 000000000046abda RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fc6ebc97ab0 RBP: 0000000020000000 R08: 00007fc6ebc97af0 R09: 0000000020000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000020000100 R13: 00007fc6ebc97ab0 R14: 0000000000000001 R15: 0000000020000140 Modules linked in: CR2: 00000000000005d0 ---[ end trace 00146354a78b09b6 ]--- RIP: 0010:bio_associate_blkg_from_css+0x331/0xb90 Code: fe 48 c7 c6 79 f7 54 82 48 c7 c7 e0 de 41 86 e8 75 04 db fe 48 8b 45 d0 49 89 46 48 e9 ec 00 00 00 e8 b3 7b e8 fe 49 8b 46 08 <48> 8b 80 d0 05 00 00 48 8b 80 90 00 00 00 4c 8b a0 f0 04 00 00 e8 RSP: 0018:ffffc90003de7b10 EFLAGS: 00010212 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc9000b9f1000 RSI: ffff88810b5f9b80 RDI: 0000000000000002 RBP: ffffc90003de7b60 R08: ffffffff8254f7ad R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000001 R12: ffffffff892f6f60 R13: ffff88810717fc00 R14: ffff888107d38700 R15: 0000000000000046 FS: 00007fc6ebc98700(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000005d0 CR3: 000000012f494000 CR4: 00000000003506e0 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 48 c7 c6 79 f7 54 82 mov $0xffffffff8254f779,%rsi 7: 48 c7 c7 e0 de 41 86 mov $0xffffffff8641dee0,%rdi e: e8 75 04 db fe callq 0xfedb0488 13: 48 8b 45 d0 mov -0x30(%rbp),%rax 17: 49 89 46 48 mov %rax,0x48(%r14) 1b: e9 ec 00 00 00 jmpq 0x10c 20: e8 b3 7b e8 fe callq 0xfee87bd8 25: 49 8b 46 08 mov 0x8(%r14),%rax * 29: 48 8b 80 d0 05 00 00 mov 0x5d0(%rax),%rax <-- trapping instruction 30: 48 8b 80 90 00 00 00 mov 0x90(%rax),%rax 37: 4c 8b a0 f0 04 00 00 mov 0x4f0(%rax),%r12 3e: e8 .byte 0xe8 Best, Wei
