syzbot


BUG: unable to handle kernel NULL pointer dereference in mark_page_accessed

Status: closed as invalid on 2020/06/20 17:31
Reported-by: syzbot+9626deae3b44a8c051b1@syzkaller.appspotmail.com
First crash: 830d, last: 830d

Sample crash report:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD a23b6067 P4D a23b6067 PUD 8f4dc067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 26760 Comm: syz-executor.5 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:252 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x43/0x60 kernel/kcov.c:202
Code: 24 74 0f 80 e6 01 74 35 8b 90 04 14 00 00 85 d2 74 2b 8b 90 e0 13 00 00 83 fa 02 75 20 48 8b 88 e8 13 00 00 8b 80 e4 13 00 00 <48> 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 c3 66 0f
RSP: 0018:ffffc9000910f2a0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00fffe000002203e RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff8197ca14 RDI: 0000000000000007
RBP: ffffea000232d700 R08: ffff888095528280 R09: fffff94000465ae1
R10: ffffea000232d707 R11: fffff94000465ae0 R12: ffffea000232d708
R13: 0000000000000000 R14: ffffea00020f1888 R15: 00000000000000f4
FS:  00007f80f594d700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000a2419000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __read_once_size include/linux/compiler.h:252 [inline]
 compound_head include/linux/page-flags.h:182 [inline]
 PageActive include/linux/page-flags.h:329 [inline]
 mark_page_accessed+0x444/0x13f0 mm/swap.c:434
 touch_buffer fs/buffer.c:63 [inline]
 __find_get_block+0x317/0xe90 fs/buffer.c:1333
 __getblk_gfp+0x33/0xae0 fs/buffer.c:1351
 sb_getblk include/linux/buffer_head.h:325 [inline]
 fat_mirror_bhs+0x23e/0x500 fs/fat/fatent.c:386
 fat_ent_write+0xfe/0x1a0 fs/fat/fatent.c:421
 fat_chain_add+0x48d/0x600 fs/fat/misc.c:130
 fat_add_cluster+0xc7/0xf0 fs/fat/inode.c:113
 __fat_get_block fs/fat/inode.c:155 [inline]
 fat_get_block+0x5ae/0x930 fs/fat/inode.c:190
 __block_write_begin_int+0x490/0x1b20 fs/buffer.c:2012
 __block_write_begin fs/buffer.c:2062 [inline]
 block_write_begin+0x58/0x2e0 fs/buffer.c:2121
 cont_write_begin+0x47e/0x7f0 fs/buffer.c:2470
 fat_write_begin+0x8d/0x120 fs/fat/inode.c:235
 generic_perform_write+0x20a/0x4e0 mm/filemap.c:3299
 __generic_file_write_iter+0x492/0x610 mm/filemap.c:3396
 generic_file_write_iter+0x3f3/0x630 mm/filemap.c:3460
 call_write_iter include/linux/fs.h:1917 [inline]
 new_sync_write+0x426/0x650 fs/read_write.c:484
 __vfs_write+0xc9/0x100 fs/read_write.c:497
 vfs_write+0x268/0x5d0 fs/read_write.c:559
 ksys_write+0x12d/0x250 fs/read_write.c:612
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca59
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f80f594cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050b0e0 RCX: 000000000045ca59
RDX: 00000000200014ee RSI: 0000000020001400 RDI: 0000000000000004
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000c7c R14: 00000000004cecd6 R15: 00007f80f594d6d4
Modules linked in:
CR2: 0000000000000000
---[ end trace 3b58131838ccd576 ]---
RIP: 0010:__read_once_size include/linux/compiler.h:252 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x43/0x60 kernel/kcov.c:202
Code: 24 74 0f 80 e6 01 74 35 8b 90 04 14 00 00 85 d2 74 2b 8b 90 e0 13 00 00 83 fa 02 75 20 48 8b 88 e8 13 00 00 8b 80 e4 13 00 00 <48> 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 c3 66 0f
RSP: 0018:ffffc9000910f2a0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00fffe000002203e RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff8197ca14 RDI: 0000000000000007
RBP: ffffea000232d700 R08: ffff888095528280 R09: fffff94000465ae1
R10: ffffea000232d707 R11: fffff94000465ae0 R12: ffffea000232d708
R13: 0000000000000000 R14: ffffea00020f1888 R15: 00000000000000f4
FS:  00007f80f594d700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005571e18b7618 CR3: 00000000a2419000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2020/06/16 15:41 upstream 7ae77150d94d baca2611 .config log report
* Struck through repros no longer work on HEAD.