bisecting fixing commit since 10b84daddbec72c6b440216a69de9a9605127f7a building syzkaller on 0174c6c8f78a3fdd002a73a5fdf559c1b0ec8c34 testing commit 10b84daddbec72c6b440216a69de9a9605127f7a with gcc (GCC) 8.1.0 kernel signature: 7f7471705acee4f419bc49eb15a0c798d4e2f3afe6534d676f9a361d83e2ed92 all runs: crashed: general protection fault in hfs_find_init testing current HEAD fb33c6510d5595144d585aa194d377cf74d31911 testing commit fb33c6510d5595144d585aa194d377cf74d31911 with gcc (GCC) 8.1.0 kernel signature: 4bcfb447618a7fe950d50ac82729681709577364149dbef0716044fcecf64d0b all runs: crashed: general protection fault in hfs_find_init revisions tested: 2, total time: 17m39.453001913s (build: 10m24.285459983s, test: 6m29.486806524s) the crash still happens on HEAD commit msg: Linux 5.6-rc6 crash: general protection fault in hfs_find_init IPVS: ftp: loaded support on port[0] = 21 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 general protection fault, probably for non-canonical address 0xdffffc0000000008: 0000 [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047] CPU: 1 PID: 4447 Comm: syz-executor3 Not tainted 5.6.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:hfs_find_init+0x73/0x180 fs/hfs/bfind.c:21 Code: ea 03 80 3c 02 00 0f 85 ee 00 00 00 4d 8d 6c 24 40 48 c7 43 18 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e ac 00 00 00 41 8b 44 24 40 be RSP: 0018:ffff8881c78bf330 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff8881c78bf3b0 RCX: 1ffff11038cafc85 RDX: 0000000000000008 RSI: ffff8881c78bf3b0 RDI: ffff8881c78bf3c8 RBP: ffff8881c78bf350 R08: ffffed10384aeeda R09: ffff8881c78bf410 R10: 0000000000000000 R11: ffff8881c25776cf R12: 0000000000000000 R13: 0000000000000040 R14: ffff8881c2577772 R15: ffff8881c78bf3b0 FS: 00007f7b77037700(0000) GS:ffff8881db100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000006fe000 CR3: 00000001c6918000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: hfs_ext_read_extent+0x17e/0xcc0 fs/hfs/extent.c:200 hfs_get_block+0x490/0x850 fs/hfs/extent.c:366 block_read_full_page+0x288/0x950 fs/buffer.c:2285 hfs_readpage+0x13/0x20 fs/hfs/inode.c:38 do_read_cache_page+0x65c/0x12d0 mm/filemap.c:2761 read_cache_page+0x45/0x70 mm/filemap.c:2852 read_mapping_page include/linux/pagemap.h:396 [inline] hfs_btree_open+0x45f/0x1070 fs/hfs/btree.c:78 hfs_mdb_get+0x1329/0x1d86 fs/hfs/mdb.c:193 hfs_fill_super+0x9b4/0x12a0 fs/hfs/super.c:407 mount_bdev+0x27b/0x340 fs/super.c:1417 hfs_mount+0x10/0x20 fs/hfs/super.c:457 legacy_get_tree+0x103/0x1f0 fs/fs_context.c:622 vfs_get_tree+0x8b/0x2d0 fs/super.c:1547 do_new_mount fs/namespace.c:2822 [inline] do_mount+0x1285/0x1b70 fs/namespace.c:3107 __do_sys_mount fs/namespace.c:3316 [inline] __se_sys_mount fs/namespace.c:3293 [inline] __x64_sys_mount+0x169/0x1c0 fs/namespace.c:3293 do_syscall_64+0xd0/0x630 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4579fa Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 dd 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 ba 8f fb ff c3 66 0f 1f 84 00 00 00 00 00 RSP: 002b:00007f7b77036bb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 00000000004579fa RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f7b77036c00 RBP: 0000000000000003 R08: 00000000200001c0 R09: 0000000020000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000666 R14: 00000000006fba30 R15: 0000000000000000 Modules linked in: ---[ end trace 12861ad74f8ecba2 ]--- RIP: 0010:hfs_find_init+0x73/0x180 fs/hfs/bfind.c:21 Code: ea 03 80 3c 02 00 0f 85 ee 00 00 00 4d 8d 6c 24 40 48 c7 43 18 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e ac 00 00 00 41 8b 44 24 40 be hfs: unable to locate alternate MDB RSP: 0018:ffff8881c78bf330 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff8881c78bf3b0 RCX: 1ffff11038cafc85 RDX: 0000000000000008 RSI: ffff8881c78bf3b0 RDI: ffff8881c78bf3c8 RBP: ffff8881c78bf350 R08: ffffed10384aeeda R09: ffff8881c78bf410 R10: 0000000000000000 R11: ffff8881c25776cf R12: 0000000000000000 R13: 0000000000000040 R14: ffff8881c2577772 R15: ffff8881c78bf3b0 hfs: continuing without an alternate MDB FS: 00007f7b77037700(0000) GS:ffff8881db100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 general protection fault, probably for non-canonical address 0xdffffc0000000008: 0000 [#2] SMP KASAN CR2: 00000000006fe000 CR3: 00000001c6918000 CR4: 00000000001406e0 KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047] CPU: 0 PID: 4452 Comm: syz-executor2 Tainted: G D 5.6.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:hfs_find_init+0x73/0x180 fs/hfs/bfind.c:21 Code: ea 03 80 3c 02 00 0f 85 ee 00 00 00 4d 8d 6c 24 40 48 c7 43 18 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e ac 00 00 00 41 8b 44 24 40 be DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 RSP: 0018:ffff8881c2b9f330 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff8881c2b9f3b0 RCX: 1ffff11038ac4b85 RDX: 0000000000000008 RSI: ffff8881c2b9f3b0 RDI: ffff8881c2b9f3c8 RBP: ffff8881c2b9f350 R08: 0000000000000000 R09: ffff8881c2b9f410 R10: 0000000000000000 R11: ffff8881c556b70f R12: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 R13: 0000000000000040 R14: ffff8881c556b7b2 R15: ffff8881c2b9f3b0 FS: 00007fda353c8700(0000) GS:ffff8881db000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcbf62cf000 CR3: 00000001c7ed4000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000