Re: [syzbot] [mm?] general protection fault in lru_gen_test_recent (2)

[syzbot <syzbot+e008db2ac01e282550ee@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in lru_gen_test_recent

DEBUG: memcg_id=0 memcg=0000000000000000 root_mem_cgroup=ffff88801cac8000
DEBUG: memcg is NULL, using root_mem_cgroup
DEBUG: after assignment memcg=ffff88801cac8000
DEBUG: about to call mem_cgroup_lruvec with memcg=ffff88801cac8000
Oops: general protection fault, probably for non-canonical address 0xdffffc00000009c0: 0000 [#1] SMP KASAN NOPTI
KASAN: probably user-memory-access in range [0x0000000000004e00-0x0000000000004e07]
CPU: 0 UID: 0 PID: 6414 Comm: syz.0.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:mem_cgroup_lruvec include/linux/memcontrol.h:720 [inline]
RIP: 0010:lru_gen_test_recent+0x14a/0x420 mm/workingset.c:282
Code: dc 7f b5 ff 48 85 db 0f 84 a4 01 00 00 e8 ce 7f b5 ff 49 8d be 00 4e 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 10 02 00 00 4d 63 ae 00 4e 00
RSP: 0018:ffffc9000177f828 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff88801cac8000 RCX: ffffffff819c8d55
RDX: 00000000000009c0 RSI: ffffffff820964a2 RDI: 0000000000004e00
RBP: ffffc9000177f8c0 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: ffff888026ad8b30 R12: ffffc9000177f8e0
R13: ffffffff90882820 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fb55eb846c0(0000) GS:ffff8880d6909000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000409000000 CR3: 0000000022e91000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 lru_gen_refault mm/workingset.c:303 [inline]
 workingset_refault+0x251/0xca0 mm/workingset.c:553
 filemap_add_folio+0x23d/0x610 mm/filemap.c:981
 do_read_cache_folio+0x23c/0x5c0 mm/filemap.c:4063
 freader_get_folio+0x33a/0x930 lib/buildid.c:58
 freader_fetch+0xbd/0x740 lib/buildid.c:101
 __build_id_parse.isra.0+0xdd/0x6c0 lib/buildid.c:289
 do_procmap_query+0xb0e/0x1080 fs/proc/task_mmu.c:733
 procfs_procmap_ioctl+0x9d/0xe0 fs/proc/task_mmu.c:813
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb55dd8f7c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb55eb84038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fb55dfe5fa0 RCX: 00007fb55dd8f7c9
RDX: 0000200000000180 RSI: 00000000c0686611 RDI: 0000000000000003
RBP: 00007fb55de13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb55dfe6038 R14: 00007fb55dfe5fa0 R15: 00007ffd3962a3c8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:mem_cgroup_lruvec include/linux/memcontrol.h:720 [inline]
RIP: 0010:lru_gen_test_recent+0x14a/0x420 mm/workingset.c:282
Code: dc 7f b5 ff 48 85 db 0f 84 a4 01 00 00 e8 ce 7f b5 ff 49 8d be 00 4e 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 10 02 00 00 4d 63 ae 00 4e 00
RSP: 0018:ffffc9000177f828 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff88801cac8000 RCX: ffffffff819c8d55
RDX: 00000000000009c0 RSI: ffffffff820964a2 RDI: 0000000000004e00
RBP: ffffc9000177f8c0 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: ffff888026ad8b30 R12: ffffc9000177f8e0
R13: ffffffff90882820 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fb55eb846c0(0000) GS:ffff8880d6909000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000409000000 CR3: 0000000022e91000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	dc 7f b5             	fdivrl -0x4b(%rdi)
   3:	ff 48 85             	decl   -0x7b(%rax)
   6:	db 0f                	fisttpl (%rdi)
   8:	84 a4 01 00 00 e8 ce 	test   %ah,-0x31180000(%rcx,%rax,1)
   f:	7f b5                	jg     0xffffffc6
  11:	ff 49 8d             	decl   -0x73(%rcx)
  14:	be 00 4e 00 00       	mov    $0x4e00,%esi
  19:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  20:	fc ff df
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	0f b6 04 02          	movzbl (%rdx,%rax,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	74 08                	je     0x3a
  32:	3c 03                	cmp    $0x3,%al
  34:	0f 8e 10 02 00 00    	jle    0x24a
  3a:	4d                   	rex.WRB
  3b:	63                   	.byte 0x63
  3c:	ae                   	scas   %es:(%rdi),%al
  3d:	00 4e 00             	add    %cl,0x0(%rsi)


Tested on:

commit:         37bb2e72 Merge tag 'staging-6.19-rc1' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13dcf21a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dbcb767d1e1208ac
dashboard link: https://syzkaller.appspot.com/bug?extid=e008db2ac01e282550ee
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14f5a992580000