syzbot


BUG: unable to handle kernel NULL pointer dereference in mempool_alloc_noprof

Status: moderation: reported on 2024/05/27 00:55
Subsystems: block
[Documentation on labels]
Reported-by: syzbot+c44fe924a6d145fb9301@syzkaller.appspotmail.com
First crash: 56d, last: 22d

Sample crash report:
bcachefs (loop3): resume_logged_ops... done
bcachefs (loop3): going read-write
bcachefs (loop3): done starting filesystem
BUG: kernel NULL pointer dereference, address: 0000000000000014
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 27aa4067 P4D 27aa4067 PUD 1511c067 PMD 0 
Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 2 PID: 8179 Comm: syz-executor.3 Not tainted 6.10.0-rc5-syzkaller-00018-g55027e689933 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:___slab_alloc+0x27a/0x1870 mm/slub.c:3610
Code: 0b 49 83 7f 28 00 0f 85 de 07 00 00 4d 89 77 28 49 83 7c 24 10 00 0f 85 45 06 00 00 4d 8b 7c 24 18 4d 85 ff 0f 84 d2 06 00 00 <49> 8b 47 10 83 bd 68 ff ff ff ff 49 89 44 24 18 74 20 49 8b 07 48
RSP: 0018:ffffc900038df110 EFLAGS: 00010002
RAX: 0000000000000000 RBX: 0000000000000202 RCX: ffffffff816bc8ae
RDX: 0000000000000001 RSI: ffffffff81e19b68 RDI: 0000000000000000
RBP: ffffc900038df1f0 R08: 0000000000000000 R09: fffffbfff283fa58
R10: ffffffff941fd2c7 R11: 0000000000000002 R12: ffffe8ffad267b30
R13: ffff88800053adc0 R14: ffff888056e6c880 R15: 0000000000000004
FS:  0000000000000000(0000) GS:ffff88802c200000(0063) knlGS:00000000f5e54b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000000000014 CR3: 000000001d050000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3757
 __slab_alloc_node mm/slub.c:3810 [inline]
 slab_alloc_node mm/slub.c:3989 [inline]
 kmem_cache_alloc_noprof+0x2ae/0x2f0 mm/slub.c:4008
 mempool_alloc_noprof+0x176/0x390 mm/mempool.c:402
 bio_alloc_bioset+0x480/0x8b0 block/bio.c:554
 bch2_writepage_io_alloc fs/bcachefs/fs-io-buffered.c:476 [inline]
 __bch2_writepage+0x107e/0x2500 fs/bcachefs/fs-io-buffered.c:610
 write_cache_pages+0xb0/0x130 mm/page-writeback.c:2591
 bch2_writepages+0x11f/0x200 fs/bcachefs/fs-io-buffered.c:650
 do_writepages+0x1a3/0x7f0 mm/page-writeback.c:2634
 filemap_fdatawrite_wbc mm/filemap.c:397 [inline]
 filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:387
 __filemap_fdatawrite_range+0xba/0x100 mm/filemap.c:430
 file_write_and_wait_range+0xd0/0x140 mm/filemap.c:788
 bch2_fsync+0xa1/0x2c0 fs/bcachefs/fs-io.c:197
 vfs_fsync_range+0x141/0x230 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2794 [inline]
 bch2_buffered_write fs/bcachefs/fs-io-buffered.c:1128 [inline]
 bch2_write_iter+0x756/0x3180 fs/bcachefs/fs-io-buffered.c:1136
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x6b6/0x1140 fs/read_write.c:590
 ksys_write+0x12f/0x260 fs/read_write.c:643
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7262579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f5e545ac EFLAGS: 00000292 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000020000180
RDX: 0000000000002000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
CR2: 0000000000000014
---[ end trace 0000000000000000 ]---
RIP: 0010:___slab_alloc+0x27a/0x1870 mm/slub.c:3610
Code: 0b 49 83 7f 28 00 0f 85 de 07 00 00 4d 89 77 28 49 83 7c 24 10 00 0f 85 45 06 00 00 4d 8b 7c 24 18 4d 85 ff 0f 84 d2 06 00 00 <49> 8b 47 10 83 bd 68 ff ff ff ff 49 89 44 24 18 74 20 49 8b 07 48
RSP: 0018:ffffc900038df110 EFLAGS: 00010002
RAX: 0000000000000000 RBX: 0000000000000202 RCX: ffffffff816bc8ae
RDX: 0000000000000001 RSI: ffffffff81e19b68 RDI: 0000000000000000
RBP: ffffc900038df1f0 R08: 0000000000000000 R09: fffffbfff283fa58
R10: ffffffff941fd2c7 R11: 0000000000000002 R12: ffffe8ffad267b30
R13: ffff88800053adc0 R14: ffff888056e6c880 R15: 0000000000000004
FS:  0000000000000000(0000) GS:ffff88802c200000(0063) knlGS:00000000f5e54b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000000000014 CR3: 000000001d050000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	49 83 7f 28 00       	cmpq   $0x0,0x28(%r15)
   5:	0f 85 de 07 00 00    	jne    0x7e9
   b:	4d 89 77 28          	mov    %r14,0x28(%r15)
   f:	49 83 7c 24 10 00    	cmpq   $0x0,0x10(%r12)
  15:	0f 85 45 06 00 00    	jne    0x660
  1b:	4d 8b 7c 24 18       	mov    0x18(%r12),%r15
  20:	4d 85 ff             	test   %r15,%r15
  23:	0f 84 d2 06 00 00    	je     0x6fb
* 29:	49 8b 47 10          	mov    0x10(%r15),%rax <-- trapping instruction
  2d:	83 bd 68 ff ff ff ff 	cmpl   $0xffffffff,-0x98(%rbp)
  34:	49 89 44 24 18       	mov    %rax,0x18(%r12)
  39:	74 20                	je     0x5b
  3b:	49 8b 07             	mov    (%r15),%rax
  3e:	48                   	rex.W

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/25 15:36 upstream 55027e689933 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 BUG: unable to handle kernel NULL pointer dereference in mempool_alloc_noprof
2024/05/28 19:15 upstream e0cce98fe279 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 BUG: unable to handle kernel NULL pointer dereference in mempool_alloc_noprof
2024/05/23 00:52 upstream 5f16eb0549ab c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 BUG: unable to handle kernel NULL pointer dereference in mempool_alloc_noprof
* Struck through repros no longer work on HEAD.