syzbot


general protection fault in ksm_scan_thread

Status: auto-obsoleted due to no activity on 2024/03/25 05:31
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+c00ebf22d66d5a066087@syzkaller.appspotmail.com
First crash: 85d, last: 85d

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000084: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000420-0x0000000000000427]
CPU: 0 PID: 35 Comm: ksmd Not tainted 6.8.0-rc1-next-20240125-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
RIP: 0010:scan_get_next_rmap_item mm/ksm.c:2641 [inline]
RIP: 0010:ksm_do_scan mm/ksm.c:2754 [inline]
RIP: 0010:ksm_scan_thread+0x35b/0x5110 mm/ksm.c:2780
Code: ff ff ff ff e8 66 50 c3 08 48 85 c0 48 89 04 24 0f 84 4e 13 00 00 e8 64 31 a6 ff 48 8b 04 24 48 8d 78 20 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 0f 85 f2 3c 00 00 4c 8b 34 24 31 ff 49 8b 5e 20 81
RSP: 0018:ffffc90000ab7ce8 EFLAGS: 00010207
RAX: 0000000000000084 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88801be85a00 RSI: ffffffff81e60e0c RDI: 0000000000000426
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff88804c621550 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555574ac750 CR3: 0000000023858000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:scan_get_next_rmap_item mm/ksm.c:2641 [inline]
RIP: 0010:ksm_do_scan mm/ksm.c:2754 [inline]
RIP: 0010:ksm_scan_thread+0x35b/0x5110 mm/ksm.c:2780
Code: ff ff ff ff e8 66 50 c3 08 48 85 c0 48 89 04 24 0f 84 4e 13 00 00 e8 64 31 a6 ff 48 8b 04 24 48 8d 78 20 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 0f 85 f2 3c 00 00 4c 8b 34 24 31 ff 49 8b 5e 20 81
RSP: 0018:ffffc90000ab7ce8 EFLAGS: 00010207
RAX: 0000000000000084 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88801be85a00 RSI: ffffffff81e60e0c RDI: 0000000000000426
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff88804c621550 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2bc2c000 CR3: 000000007ec3a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 4 bytes skipped:
   0:	e8 66 50 c3 08       	call   0x8c3506b
   5:	48 85 c0             	test   %rax,%rax
   8:	48 89 04 24          	mov    %rax,(%rsp)
   c:	0f 84 4e 13 00 00    	je     0x1360
  12:	e8 64 31 a6 ff       	call   0xffa6317b
  17:	48 8b 04 24          	mov    (%rsp),%rax
  1b:	48 8d 78 20          	lea    0x20(%rax),%rdi
  1f:	48 89 f8             	mov    %rdi,%rax
  22:	48 c1 e8 03          	shr    $0x3,%rax
* 26:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1) <-- trapping instruction
  2b:	0f 85 f2 3c 00 00    	jne    0x3d23
  31:	4c 8b 34 24          	mov    (%rsp),%r14
  35:	31 ff                	xor    %edi,%edi
  37:	49 8b 5e 20          	mov    0x20(%r14),%rbx
  3b:	81                   	.byte 0x81

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/01/25 05:30 linux-next 01af33cc9894 1e153dc8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in ksm_scan_thread
* Struck through repros no longer work on HEAD.