bisecting fixing commit since 10b84daddbec72c6b440216a69de9a9605127f7a building syzkaller on 0174c6c8f78a3fdd002a73a5fdf559c1b0ec8c34 testing commit 10b84daddbec72c6b440216a69de9a9605127f7a with gcc (GCC) 8.1.0 kernel signature: 677f2c48b5cd944d1f20b82155fbfe921ec25abb7d91b720debb9bd2aac8ff7b all runs: crashed: general protection fault in hfs_find_init testing current HEAD 659caaf65dc9c7150aa3e80225ec6e66b25ab3ce testing commit 659caaf65dc9c7150aa3e80225ec6e66b25ab3ce with gcc (GCC) 8.1.0 kernel signature: 4d3d3824da2f4090c5e82e75aa232a66a92aa20929df9be609f54467824e7796 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in hfs_find_init revisions tested: 2, total time: 14m31.269731681s (build: 8m19.279996234s, test: 5m23.174042764s) the crash still happens on HEAD commit msg: Merge tag 'ceph-for-5.10-rc3' of git://github.com/ceph/ceph-client crash: BUG: unable to handle kernel NULL pointer dereference in hfs_find_init IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 hfs: unable to locate alternate MDB hfs: continuing without an alternate MDB hfs: unable to locate alternate MDB BUG: kernel NULL pointer dereference, address: 0000000000000040 hfs: continuing without an alternate MDB #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 10fefc067 P4D 10fefc067 PUD 10fefd067 PMD 0 Oops: 0000 [#1] SMP CPU: 1 PID: 3762 Comm: syz-executor1 Not tainted 5.10.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:hfs_find_init+0x19/0x60 fs/hfs/bfind.c:21 Code: fe ff ff ff eb 8d cc cc cc cc cc cc cc cc cc cc cc 55 48 89 e5 41 54 49 89 f4 53 48 89 fb 48 89 7e 10 48 c7 46 18 00 00 00 00 <8b> 47 40 be c0 0c 00 00 8d 7c 00 04 e8 46 95 e0 ff 48 85 c0 74 23 RSP: 0018:ffffc9000043b9a0 EFLAGS: 00010246 RAX: ffff88810fb70400 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffc9000043b9c0 RDI: 0000000000000000 RBP: ffffc9000043b9b0 R08: ffffffff84fe4478 R09: 703ef4858757e957 R10: ffffc9000043ba18 R11: 0000000000000282 R12: ffffc9000043b9c0 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88810e814498 FS: 00007f45b8cc3700(0000) GS:ffff888237d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000040 CR3: 000000010fefb000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: hfs_ext_read_extent+0x53/0x1a0 fs/hfs/extent.c:200 hfs_get_block+0x162/0x220 fs/hfs/extent.c:366 block_read_full_page+0x10b/0x3c0 fs/buffer.c:2288 hfs_readpage+0x13/0x20 fs/hfs/inode.c:39 do_read_cache_page+0x5e1/0x790 mm/filemap.c:2999 read_cache_page+0xd/0x10 mm/filemap.c:3098 read_mapping_page include/linux/pagemap.h:500 [inline] hfs_btree_open+0x136/0x340 fs/hfs/btree.c:78 hfs_mdb_get+0x4ee/0x610 fs/hfs/mdb.c:199 hfs_fill_super+0x361/0x630 fs/hfs/super.c:406 mount_bdev+0x197/0x1d0 fs/super.c:1419 hfs_mount+0x10/0x20 fs/hfs/super.c:456 legacy_get_tree+0x2f/0x50 fs/fs_context.c:592 vfs_get_tree+0x28/0xc0 fs/super.c:1549 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x765/0xaf0 fs/namespace.c:3205 do_mount+0x77/0x90 fs/namespace.c:3218 __do_sys_mount fs/namespace.c:3426 [inline] __se_sys_mount fs/namespace.c:3403 [inline] __x64_sys_mount+0xc0/0xe0 fs/namespace.c:3403 do_syscall_64+0x37/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x457a7a Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 5d 8f fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 3a 8f fb ff c3 66 0f 1f 84 00 00 00 00 00 RSP: 002b:00007f45b8cc2bb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 0000000000457a7a RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f45b8cc2c00 RBP: 0000000000000003 R08: 00000000200001c0 R09: 0000000020000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000666 R14: 00000000006fba30 R15: 0000000000000000 Modules linked in: CR2: 0000000000000040 ---[ end trace 4e1064b77f7b00aa ]--- RIP: 0010:hfs_find_init+0x19/0x60 fs/hfs/bfind.c:21 Code: fe ff ff ff eb 8d cc cc cc cc cc cc cc cc cc cc cc 55 48 89 e5 41 54 49 89 f4 53 48 89 fb 48 89 7e 10 48 c7 46 18 00 00 00 00 <8b> 47 40 be c0 0c 00 00 8d 7c 00 04 e8 46 95 e0 ff 48 85 c0 74 23 BUG: kernel NULL pointer dereference, address: 0000000000000040 RSP: 0018:ffffc9000043b9a0 EFLAGS: 00010246 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 10fb7a067 P4D 10fb7a067 PUD 10fb79067 PMD 0 Oops: 0000 [#2] SMP CPU: 0 PID: 3763 Comm: syz-executor3 Tainted: G D 5.10.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:hfs_find_init+0x19/0x60 fs/hfs/bfind.c:21 Code: fe ff ff ff eb 8d cc cc cc cc cc cc cc cc cc cc cc 55 48 89 e5 41 54 49 89 f4 53 48 89 fb 48 89 7e 10 48 c7 46 18 00 00 00 00 <8b> 47 40 be c0 0c 00 00 8d 7c 00 04 e8 46 95 e0 ff 48 85 c0 74 23 RSP: 0018:ffffc900004639a0 EFLAGS: 00010246 RAX: ffff88810fa4a000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffc900004639c0 RDI: 0000000000000000 RBP: ffffc900004639b0 R08: 0000000000000001 R09: 0000000000000000 R10: ffffc90000463a18 R11: 0000000000000800 R12: ffffc900004639c0 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88810e8325e8 FS: 00007fed97638700(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000 RAX: ffff88810fb70400 RBX: 0000000000000000 RCX: 0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000040 CR3: 000000010fb7b000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: RDX: 0000000000000000 RSI: ffffc9000043b9c0 RDI: 0000000000000000 hfs_ext_read_extent+0x53/0x1a0 fs/hfs/extent.c:200 hfs_get_block+0x162/0x220 fs/hfs/extent.c:366 block_read_full_page+0x10b/0x3c0 fs/buffer.c:2288 RBP: ffffc9000043b9b0 R08: ffffffff84fe4478 R09: 703ef4858757e957 hfs_readpage+0x13/0x20 fs/hfs/inode.c:39 do_read_cache_page+0x5e1/0x790 mm/filemap.c:2999 R10: ffffc9000043ba18 R11: 0000000000000282 R12: ffffc9000043b9c0 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88810e814498 read_cache_page+0xd/0x10 mm/filemap.c:3098 read_mapping_page include/linux/pagemap.h:500 [inline] hfs_btree_open+0x136/0x340 fs/hfs/btree.c:78 FS: 00007f45b8cc3700(0000) GS:ffff888237d00000(0000) knlGS:0000000000000000 hfs_mdb_get+0x4ee/0x610 fs/hfs/mdb.c:199 hfs_fill_super+0x361/0x630 fs/hfs/super.c:406 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 mount_bdev+0x197/0x1d0 fs/super.c:1419 CR2: 0000000000000040 CR3: 000000010fefb000 CR4: 00000000001506e0 hfs_mount+0x10/0x20 fs/hfs/super.c:456 legacy_get_tree+0x2f/0x50 fs/fs_context.c:592 vfs_get_tree+0x28/0xc0 fs/super.c:1549 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x765/0xaf0 fs/namespace.c:3205 do_mount+0x77/0x90 fs/namespace.c:3218 __do_sys_mount fs/namespace.c:3426 [inline] __se_sys_mount fs/namespace.c:3403 [inline] __x64_sys_mount+0xc0/0xe0 fs/namespace.c:3403 do_syscall_64+0x37/0x80 arch/x86/entry/common.c:46 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x457a7a Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 5d 8f fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 3a 8f fb ff c3 66 0f 1f 84 00 00 00 00 00