bisecting fixing commit since cb95712138ec5e480db5160b41172bbc6f6494cc building syzkaller on cef5ae6814696260ff58c538a1b6044af90c5979 testing commit cb95712138ec5e480db5160b41172bbc6f6494cc compiler: gcc (GCC) 8.4.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: 9b18ca80919f5801857d441e22eb090b0b0b8a9a34d95381668c75c616aa0623 all runs: crashed: general protection fault in bdev_read_page testing current HEAD aa829778b16f15266fefe2640f04931b16ce39c0 testing commit aa829778b16f15266fefe2640f04931b16ce39c0 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1 kernel signature: 4d902b1c69b812cae1a8444a10b2d585a93432e477155c79a4e3f202396e5802 all runs: crashed: general protection fault in bdev_read_page revisions tested: 2, total time: 19m28.127236985s (build: 12m8.363505818s, test: 6m35.327129107s) the crash still happens on HEAD commit msg: Merge tag 'locking-debug-2021-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip crash: general protection fault in bdev_read_page general protection fault, probably for non-canonical address 0xdffffc00000000b9: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x00000000000005c8-0x00000000000005cf] CPU: 0 PID: 8099 Comm: systemd-udevd Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:bdev_read_page+0x2c/0x240 fs/block_dev.c:734 Code: 00 00 00 00 00 fc ff df 41 57 41 56 49 89 d6 41 55 41 54 55 48 8d af c8 05 00 00 48 89 ea 53 48 89 fb 48 c1 ea 03 48 83 ec 10 <80> 3c 02 00 48 89 34 24 0f 85 a3 01 00 00 4c 8b a3 c8 05 00 00 48 RSP: 0018:ffffc90007a9f3e0 EFLAGS: 00010282 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000014 RDX: 00000000000000b9 RSI: fff8918ac0600000 RDI: 0000000000000000 RBP: 00000000000005c8 R08: 0000000000000001 R09: ffffea00040fb907 R10: fffff9400081f720 R11: ffffffff81a0d24c R12: ffffc90007a9f5f0 R13: fff8918ac0600000 R14: ffffea00040fb900 R15: 0000000000000000 FS: 00007f7e1b0b08c0(0000) GS:ffff8881f6400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000055d000 CR3: 0000000103582005 CR4: 00000000001706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: do_mpage_readpage+0xd5f/0x18d0 fs/mpage.c:302 mpage_readahead+0x2c0/0x6c0 fs/mpage.c:389 read_pages+0x1b0/0x7c0 mm/readahead.c:130 page_cache_ra_unbounded+0x47c/0x7c0 mm/readahead.c:239 do_page_cache_ra mm/readahead.c:269 [inline] force_page_cache_ra+0x301/0x560 mm/readahead.c:301 page_cache_sync_readahead include/linux/pagemap.h:884 [inline] filemap_get_pages+0x253/0x1380 mm/filemap.c:2548 filemap_read+0x261/0xb60 mm/filemap.c:2631 blkdev_read_iter+0xfb/0x180 fs/block_dev.c:1488 call_read_iter include/linux/fs.h:2157 [inline] new_sync_read+0x35d/0x5f0 fs/read_write.c:404 vfs_read+0x265/0x4c0 fs/read_write.c:485 ksys_read+0xf4/0x1d0 fs/read_write.c:623 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f7e1a1f6210 Code: 73 01 c3 48 8b 0d 98 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d b9 c1 20 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 4e fc ff ff 48 89 04 24 RSP: 002b:00007ffd736b9bc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00005616a796c670 RCX: 00007f7e1a1f6210 RDX: 0000000000000400 RSI: 00005616a796c698 RDI: 000000000000000f RBP: 00005616a7967e60 R08: 00007f7e1a1e0f58 R09: 0000000000000430 R10: 000000000000006d R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000400 R14: 00005616a7967eb0 R15: 0000000000000400 Modules linked in: ---[ end trace b579ea60bf0c6410 ]--- RIP: 0010:bdev_read_page+0x2c/0x240 fs/block_dev.c:734 Code: 00 00 00 00 00 fc ff df 41 57 41 56 49 89 d6 41 55 41 54 55 48 8d af c8 05 00 00 48 89 ea 53 48 89 fb 48 c1 ea 03 48 83 ec 10 <80> 3c 02 00 48 89 34 24 0f 85 a3 01 00 00 4c 8b a3 c8 05 00 00 48 RSP: 0018:ffffc90007a9f3e0 EFLAGS: 00010282 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000014 RDX: 00000000000000b9 RSI: fff8918ac0600000 RDI: 0000000000000000 RBP: 00000000000005c8 R08: 0000000000000001 R09: ffffea00040fb907 R10: fffff9400081f720 R11: ffffffff81a0d24c R12: ffffc90007a9f5f0 R13: fff8918ac0600000 R14: ffffea00040fb900 R15: 0000000000000000 FS: 00007f7e1b0b08c0(0000) GS:ffff8881f6400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd7377d6b0 CR3: 0000000103582004 CR4: 00000000001706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess), 7 bytes skipped: 0: df 41 57 filds 0x57(%rcx) 3: 41 56 push %r14 5: 49 89 d6 mov %rdx,%r14 8: 41 55 push %r13 a: 41 54 push %r12 c: 55 push %rbp d: 48 8d af c8 05 00 00 lea 0x5c8(%rdi),%rbp 14: 48 89 ea mov %rbp,%rdx 17: 53 push %rbx 18: 48 89 fb mov %rdi,%rbx 1b: 48 c1 ea 03 shr $0x3,%rdx 1f: 48 83 ec 10 sub $0x10,%rsp * 23: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction 27: 48 89 34 24 mov %rsi,(%rsp) 2b: 0f 85 a3 01 00 00 jne 0x1d4 31: 4c 8b a3 c8 05 00 00 mov 0x5c8(%rbx),%r12 38: 48 rex.W