Message-ID: <67e57c41.050a0220.2f068f.0034.GAE@google.com>
Date: Thu, 27 Mar 2025 09:26:41 -0700
From: syzbot <syzbot+3b6c5c6a1d0119b687a1@...kaller.appspotmail.com>
To: dhowells@...hat.com, linux-afs@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, marc.dionne@...istor.com, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [afs?] BUG: sleeping function called from invalid context in __alloc_frozen_pages_noprof

Hello,

syzbot found the following issue on:

HEAD commit:    2df0c02dab82 x86 boot build: make git ignore stale 'tools'..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15bcc198580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5f1762820c18874b
dashboard link: https://syzkaller.appspot.com/bug?extid=3b6c5c6a1d0119b687a1
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=114ffc4c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1580a804580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7fe089500003/disk-2df0c02d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d8df5abbd7c5/vmlinux-2df0c02d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/09d23e93d3a8/bzImage-2df0c02d.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/70d29040b480/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=1180a804580000)

The issue was bisected to:

commit 1d0b929fc070b4115403a0a6206a0c6a62dd61f5
Author: David Howells <dhowells@...hat.com>
Date:   Mon Feb 24 09:52:58 2025 +0000

    afs: Change dynroot to create contents on demand

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1207ade4580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1107ade4580000
console output: https://syzkaller.appspot.com/x/log.txt?x=1607ade4580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3b6c5c6a1d0119b687a1@...kaller.appspotmail.com
Fixes: 1d0b929fc070 ("afs: Change dynroot to create contents on demand")

BUG: sleeping function called from invalid context at ./include/linux/sched/mm.h:321
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 5828, name: syz-executor995
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
4 locks held by syz-executor995/5828:
 #0: ffff8880332ef0b8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x310 fs/file.c:1213
 #1: ffff888053d08148 (&type->i_mutex_dir_key#7){.+.+}-{4:4}, at: iterate_dir+0x4a6/0x760 fs/readdir.c:101
 #2: ffffffff8eb3a760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #2: ffffffff8eb3a760 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #2: ffffffff8eb3a760 (rcu_read_lock){....}-{1:3}, at: afs_dynroot_readdir+0x466/0xbe0 fs/afs/dynroot.c:351
 #3: ffff88806d7fed20 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:209 [inline]
 #3: ffff88806d7fed20 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/memory.c:6237 [inline]
 #3: ffff88806d7fed20 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:6297
CPU: 1 UID: 0 PID: 5828 Comm: syz-executor995 Not tainted 6.14.0-syzkaller-01103-g2df0c02dab82 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 __might_resched+0x558/0x6c0 kernel/sched/core.c:8798
 might_alloc include/linux/sched/mm.h:321 [inline]
 prepare_alloc_pages+0x1cc/0x5c0 mm/page_alloc.c:4513
 __alloc_frozen_pages_noprof+0x181/0x7b0 mm/page_alloc.c:4729
 alloc_pages_mpol+0x339/0x690 mm/mempolicy.c:2301
 folio_alloc_mpol_noprof mm/mempolicy.c:2320 [inline]
 vma_alloc_folio_noprof+0x12d/0x260 mm/mempolicy.c:2355
 folio_prealloc+0x2e/0x170
 alloc_anon_folio mm/memory.c:4834 [inline]
 do_anonymous_page mm/memory.c:4891 [inline]
 do_pte_missing mm/memory.c:4057 [inline]
 handle_pte_fault mm/memory.c:5888 [inline]
 __handle_mm_fault+0x32e8/0x6ef0 mm/memory.c:6031
 handle_mm_fault+0x2c1/0x7e0 mm/memory.c:6200
 do_user_addr_fault arch/x86/mm/fault.c:1388 [inline]
 handle_page_fault arch/x86/mm/fault.c:1480 [inline]
 exc_page_fault+0x2bb/0x8b0 arch/x86/mm/fault.c:1538
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:filldir+0x2c4/0x6a0 fs/readdir.c:292
Code: 87 55 02 00 00 0f 01 cb 0f ae e8 48 8b 44 24 30 49 89 46 08 48 8b 4c 24 10 48 8b 44 24 60 48 89 01 48 8b 44 24 18 8b 6c 24 3c <66> 89 41 10 48 98 40 88 6c 01 ff 48 89 44 24 30 4d 63 f5 42 c6 44
RSP: 0018:ffffc90003a37be0 EFLAGS: 00050283
RAX: 0000000000000020 RBX: 0000200000002010 RCX: 0000200000001ff0
RDX: 0000000000000000 RSI: 0000200000001fd8 RDI: 0000200000002010
RBP: 0000000000000004 R08: ffffffff8240768d R09: 1ffff1100a7fa780
R10: dffffc0000000000 R11: ffffed100a7fa781 R12: ffff888029500e41
R13: 0000000000000005 R14: 0000200000001fd8 R15: 00007ffffffff000
 dir_emit include/linux/fs.h:3853 [inline]
 afs_dynroot_readdir_cells fs/afs/dynroot.c:310 [inline]
 afs_dynroot_readdir+0x814/0xbe0 fs/afs/dynroot.c:352
 iterate_dir+0x5a9/0x760 fs/readdir.c:108
 __do_sys_getdents fs/readdir.c:322 [inline]
 __se_sys_getdents+0x1ff/0x4e0 fs/readdir.c:308
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3db8a3a419
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff5882c0e8 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 65726f6e67693d72 RCX: 00007f3db8a3a419
RDX: 00000000000000b8 RSI: 0000200000001fc0 RDI: 0000000000000004
RBP: 00007fff5882c0f8 R08: 6c616b7a79732f2e R09: 6c616b7a79732f2e
R10: 6c616b7a79732f2e R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff5882c358 R14: 000000
----------------
Code disassembly (best guess):
   0:	87 55 02             	xchg   %edx,0x2(%rbp)
   3:	00 00                	add    %al,(%rax)
   5:	0f 01 cb             	stac
   8:	0f ae e8             	lfence
   b:	48 8b 44 24 30       	mov    0x30(%rsp),%rax
  10:	49 89 46 08          	mov    %rax,0x8(%r14)
  14:	48 8b 4c 24 10       	mov    0x10(%rsp),%rcx
  19:	48 8b 44 24 60       	mov    0x60(%rsp),%rax
  1e:	48 89 01             	mov    %rax,(%rcx)
  21:	48 8b 44 24 18       	mov    0x18(%rsp),%rax
  26:	8b 6c 24 3c          	mov    0x3c(%rsp),%ebp
* 2a:	66 89 41 10          	mov    %ax,0x10(%rcx) <-- trapping instruction
  2e:	48 98                	cltq
  30:	40 88 6c 01 ff       	mov    %bpl,-0x1(%rcx,%rax,1)
  35:	48 89 44 24 30       	mov    %rax,0x30(%rsp)
  3a:	4d 63 f5             	movslq %r13d,%r14
  3d:	42                   	rex.X
  3e:	c6                   	.byte 0xc6
  3f:	44                   	rex.R


---
This report is generated by a bot. It may contain errors.
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If the report is already addressed, let syzbot know by replying with:
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