linux-kernel - Bug: soft lockup in exfat_clear

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Message-Id: <8F76A19F-2EFD-4DD4-A4B1-9F5C644B69EA@m.fudan.edu.cn>
Date: Mon, 6 Jan 2025 16:45:37 +0800
From: Kun Hu <huk23@...udan.edu.cn>
To: linkinjeon@...nel.org,
 sj1557.seo@...sung.com,
 yuezhang.mo@...y.com
Cc: linux-fsdevel@...r.kernel.org,
 linux-kernel@...r.kernel.org,
 "jjtan24@...udan.edu.cn" <jjtan24@...udan.edu.cn>
Subject: Bug: soft lockup in exfat_clear_bitmap

Hello,

When using our customized fuzzer tool to fuzz the latest Linux kernel, the following crash
was triggered.

HEAD commit: fc033cf25e612e840e545f8d5ad2edd6ba613ed5
git tree: upstream
Console output: https://drive.google.com/file/d/1aWtDTAUFlAzvMI7YM_TLWbfbyqKFB71i/view?usp=drive_link
Kernel config: https://drive.google.com/file/d/1n2sLNg-YcIgZqhhQqyMPTDWM_N1Pqz73/view?usp=sharing
C reproducer: https://drive.google.com/file/d/1oXFZgdxZDCrcZTmyatmI6TeYoHCaIxEA/view?usp=drive_link
Syzlang reproducer: https://drive.google.com/file/d/1KX9cnANDRzXZ1FjKl3uv6rSFC-5kLsko/view?usp=sharing


If you fix this issue, please add the following tag to the commit:
Reported-by: Kun Hu <huk23@...udan.edu.cn>, Jiaji Qin <jjtan24@...udan.edu.cn>

watchdog: BUG: soft lockup - CPU#1 stuck for 26s! [syz-executor140:420]
Modules linked in:
irq event stamp: 163590
hardirqs last  enabled at (163589): [<ffffffff9c4d07eb>] irqentry_exit+0x3b/0x90 kernel/entry/common.c:357
hardirqs last disabled at (163590): [<ffffffff9c4cedbf>] sysvec_apic_timer_interrupt+0xf/0xb0 arch/x86/kernel/apic/apic.c:1049
softirqs last  enabled at (163576): [<ffffffff9450f554>] softirq_handle_end kernel/softirq.c:407 [inline]
softirqs last  enabled at (163576): [<ffffffff9450f554>] handle_softirqs+0x544/0x870 kernel/softirq.c:589
softirqs last disabled at (163555): [<ffffffff9451120e>] __do_softirq kernel/softirq.c:595 [inline]
softirqs last disabled at (163555): [<ffffffff9451120e>] invoke_softirq kernel/softirq.c:435 [inline]
softirqs last disabled at (163555): [<ffffffff9451120e>] __irq_exit_rcu kernel/softirq.c:662 [inline]
softirqs last disabled at (163555): [<ffffffff9451120e>] irq_exit_rcu+0xee/0x140 kernel/softirq.c:678
CPU: 1 UID: 0 PID: 420 Comm: syz-executor140 Not tainted 6.13.0-rc5 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:exfat_clear_bitmap+0x3f1/0x580 fs/exfat/balloc.c:174
Code: 24 60 01 00 00 b9 40 0c 00 00 4c 89 fa e8 57 10 ff 01 bf a1 ff ff ff 89 c3 89 c6 e8 49 52 5f ff 83 fb a1 74 13 48 83 c4 18 5b <5d> 41 5c 41 5d 41 5e 41 5f e9 01 50 5f ff e8 fc 4f 5f ff 49 8d b4
RSP: 0018:ffa00000035f7a90 EFLAGS: 00000286
RAX: 0000000000000000 RBX: 0000000000006ccc RCX: ffffffff952a4d03
RDX: 0000000000000011 RSI: ff110000118ba340 RDI: 0000000000000003
RBP: ff110000131cc000 R08: 0000000000000000 R09: fffffbfff4d5f0ed
R10: fffffbfff4d5f0ec R11: 0000000000000001 R12: ff110000131ce000
R13: 0000000000000011 R14: 0000000000000000 R15: 0000000006cccf6b
FS:  000055556ed2d880(0000) GS:ff11000053a80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe1b6fdd18 CR3: 000000000db32002 CR4: 0000000000771ef0
PKRU: 55555554
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 __exfat_free_cluster+0x775/0x980 fs/exfat/fatent.c:192
 exfat_free_cluster+0x7a/0x100 fs/exfat/fatent.c:232
 __exfat_truncate+0x6bf/0x900 fs/exfat/file.c:235
 exfat_evict_inode+0x10d/0x1a0 fs/exfat/inode.c:683
 evict+0x403/0x880 fs/inode.c:796
 iput_final fs/inode.c:1946 [inline]
 iput fs/inode.c:1972 [inline]
 iput+0x51c/0x830 fs/inode.c:1958
 do_unlinkat+0x5c7/0x750 fs/namei.c:4594
 __do_sys_unlink fs/namei.c:4635 [inline]
 __se_sys_unlink fs/namei.c:4633 [inline]
 __x64_sys_unlink+0x40/0x50 fs/namei.c:4633
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc3/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff5d82fb1db
Code: 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe1b6ff558 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff5d82fb1db
RDX: 00007ffe1b6ff580 RSI: 00007ffe1b6ff580 RDI: 00007ffe1b6ff610
RBP: 00007ffe1b6ff610 R08: 0000000000000001 R09: 00007ffe1b6ff3e0
R10: 00000000fffffff7 R11: 0000000000000206 R12: 00007ffe1b700710
R13: 000055556ed36bb0 R14: 00007ffe1b6ff578 R15: 0000000000000001
 </TASK>


---------------
thanks,
Kun Hu