[syzbot] [reiserfs?] general protection fault in ext4_file_write_iter

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Oct 21, 2023, 1:55:50 PM10/21/23
to b...@alien8.de, dave....@linux.intel.com, h...@zytor.com, jpoi...@kernel.org, linux-...@vger.kernel.org, linux-...@vger.kernel.org, mi...@redhat.com, pet...@infradead.org, reiserf...@vger.kernel.org, syzkall...@googlegroups.com, tg...@linutronix.de, x...@kernel.org
Hello,

syzbot found the following issue on:

HEAD commit: 213f891525c2 Merge tag 'probes-fixes-v6.6-rc6' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=126daea9680000
kernel config: https://syzkaller.appspot.com/x/.config?x=20c01df4ad8f1c16
dashboard link: https://syzkaller.appspot.com/bug?extid=a2f32f54c8006a00d777
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1231cae1680000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12178005680000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/451be82930dd/disk-213f8915.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ced0744b1f8f/vmlinux-213f8915.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c1326b71b235/bzImage-213f8915.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/271887eb86fe/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a2f32f...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc00400000c5: 0000 [#1] PREEMPT SMP KASAN
KASAN: probably user-memory-access in range [0x0000000200000628-0x000000020000062f]
CPU: 0 PID: 5032 Comm: syz-executor165 Not tainted 6.6.0-rc6-syzkaller-00029-g213f891525c2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
==================================================================
BUG: KASAN: out-of-bounds in console_flush_all+0xf23/0xfb0 kernel/printk/printk.c:2976
Read of size 8 at addr ffffc9000349ef10 by task syz-executor165/5032

CPU: 0 PID: 5032 Comm: syz-executor165 Not tainted 6.6.0-rc6-syzkaller-00029-g213f891525c2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xc4/0x620 mm/kasan/report.c:475
kasan_report+0xda/0x110 mm/kasan/report.c:588
console_flush_all+0xf23/0xfb0 kernel/printk/printk.c:2976
console_unlock+0x10c/0x260 kernel/printk/printk.c:3035
vprintk_emit+0x17f/0x5f0 kernel/printk/printk.c:2307
vprintk+0x7b/0x90 kernel/printk/printk_safe.c:45
_printk+0xc8/0x100 kernel/printk/printk.c:2332
dump_stack_print_info+0x12e/0x150 lib/dump_stack.c:66
show_regs+0x1a/0xa0 arch/x86/kernel/dumpstack.c:469
__die_body arch/x86/kernel/dumpstack.c:420 [inline]
die_addr+0x4f/0xd0 arch/x86/kernel/dumpstack.c:460
__exc_general_protection arch/x86/kernel/traps.c:697 [inline]
exc_general_protection+0x154/0x230 arch/x86/kernel/traps.c:642
asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:564
RIP: 0010:EXT4_SB fs/ext4/ext4.h:1746 [inline]
RIP: 0010:ext4_forced_shutdown fs/ext4/ext4.h:2231 [inline]
RIP: 0010:ext4_file_write_iter+0x103/0x1860 fs/ext4/file.c:707
Code: 48 c1 ea 03 80 3c 02 00 0f 85 5e 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5d 28 48 8d bb 28 06 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 2e 15 00 00 4c 8b a3 28 06 00 00 be 08 00 00 00
RSP: 0000:ffffc9000349f270 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000200000001 RCX: 0000000000000000
RDX: 00000000400000c5 RSI: ffffffff822ede7a RDI: 0000000200000629
RBP: ffff88807365d830 R08: 0000000000000005 R09: 0000000000000007
R10: 0000000000000004 R11: ffffffff8a601206 R12: ffffc9000349f5c8
R13: ffffc9000349f3f0 R14: 0000000000000002 R15: ffff8880267ae2d0
__kernel_write_iter+0x261/0x7e0 fs/read_write.c:517
__kernel_write+0xf6/0x140 fs/read_write.c:537
__dump_emit fs/coredump.c:813 [inline]
dump_emit+0x21d/0x330 fs/coredump.c:850
elf_core_dump+0x2082/0x3900 fs/binfmt_elf.c:2094
do_coredump+0x2c96/0x3fc0 fs/coredump.c:764
get_signal+0x2434/0x2790 kernel/signal.c:2878
arch_do_signal_or_restart+0x90/0x7f0 arch/x86/kernel/signal.c:309
exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204
irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:309
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0033:0x7f1369fb0833
Code: 00 00 00 02 00 00 00 48 00 04 00 00 00 00 00 01 00 00 00 02 00 00 00 48 00 04 00 00 00 00 00 01 00 00 00 02 00 00 00 48 00 04 <00> 00 00 00 00 01 00 00 00 02 00 00 00 48 00 04 00 00 00 00 00 01
RSP: 002b:00007fffac036608 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 00007fffac036690 RCX: 00007f1369fb0833
RDX: 00007fffac036620 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000002 R08: 0000000000000065 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000f4240
R13: 0000000000018c01 R14: 00007fffac036664 R15: 00007fffac036680
</TASK>

The buggy address belongs to stack of task syz-executor165/5032

The buggy address belongs to the virtual mapping at
[ffffc90003498000, ffffc900034a1000) created by:
kernel_clone+0xfd/0x920 kernel/fork.c:2909

The buggy address belongs to the physical page:
page:ffffea0001fbfac0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7efeb
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_ZERO), pid 4993, tgid 4993 (dhcpcd-run-hook), ts 88329486010, free_ts 72453205616
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
prep_new_page mm/page_alloc.c:1543 [inline]
get_page_from_freelist+0xee0/0x2f20 mm/page_alloc.c:3170
__alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4426
alloc_pages+0x1a9/0x270 mm/mempolicy.c:2297
vm_area_alloc_pages mm/vmalloc.c:3063 [inline]
__vmalloc_area_node mm/vmalloc.c:3139 [inline]
__vmalloc_node_range+0xa6e/0x1540 mm/vmalloc.c:3320
alloc_thread_stack_node kernel/fork.c:309 [inline]
dup_task_struct kernel/fork.c:1118 [inline]
copy_process+0x13e3/0x73f0 kernel/fork.c:2327
kernel_clone+0xfd/0x920 kernel/fork.c:2909
__do_sys_clone+0xba/0x100 kernel/fork.c:3052
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1136 [inline]
free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2312
free_unref_page+0x33/0x3b0 mm/page_alloc.c:2405
slab_destroy mm/slab.c:1608 [inline]
slabs_destroy+0x85/0xc0 mm/slab.c:1628
cache_flusharray mm/slab.c:3341 [inline]
___cache_free+0x2b7/0x420 mm/slab.c:3404
qlink_free mm/kasan/quarantine.c:166 [inline]
qlist_free_all+0x4c/0x1b0 mm/kasan/quarantine.c:185
kasan_quarantine_reduce+0x18e/0x1d0 mm/kasan/quarantine.c:292
__kasan_slab_alloc+0x65/0x90 mm/kasan/common.c:305
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook mm/slab.h:762 [inline]
slab_alloc_node mm/slab.c:3237 [inline]
__kmem_cache_alloc_node+0x163/0x470 mm/slab.c:3521
__do_kmalloc_node mm/slab_common.c:1022 [inline]
__kmalloc+0x4f/0x100 mm/slab_common.c:1036
kmalloc include/linux/slab.h:603 [inline]
tomoyo_add_entry security/tomoyo/common.c:2023 [inline]
tomoyo_supervisor+0xcdb/0xea0 security/tomoyo/common.c:2095
tomoyo_audit_path_log security/tomoyo/file.c:168 [inline]
tomoyo_path_permission security/tomoyo/file.c:587 [inline]
tomoyo_path_permission+0x270/0x3b0 security/tomoyo/file.c:573
tomoyo_path_perm+0x35a/0x450 security/tomoyo/file.c:838
security_inode_getattr+0xf1/0x150 security/security.c:2153
vfs_getattr fs/stat.c:169 [inline]
vfs_fstat+0x4f/0xc0 fs/stat.c:194
vfs_fstatat+0x130/0x140 fs/stat.c:291
__do_sys_newfstatat+0x98/0x110 fs/stat.c:459

Memory state around the buggy address:
ffffc9000349ee00: 48 00 04 00 00 00 00 00 01 00 00 00 02 00 00 00
ffffc9000349ee80: 48 00 04 00 00 00 00 00 01 00 00 00 02 00 00 00
>ffffc9000349ef00: 48 00 04 00 00 00 00 00 01 00 00 00 02 00 00 00
^
ffffc9000349ef80: 48 00 04 00 00 00 00 00 01 00 00 00 02 00 00 00
ffffc9000349f000: 48 00 04 00 00 00 00 00 01 00 00 00 02 00 00 00
==================================================================
----------------
Code disassembly (best guess):
0: 48 c1 ea 03 shr $0x3,%rdx
4: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
8: 0f 85 5e 15 00 00 jne 0x156c
e: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
15: fc ff df
18: 48 8b 5d 28 mov 0x28(%rbp),%rbx
1c: 48 8d bb 28 06 00 00 lea 0x628(%rbx),%rdi
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 2e 15 00 00 jne 0x1562
34: 4c 8b a3 28 06 00 00 mov 0x628(%rbx),%r12
3b: be 08 00 00 00 mov $0x8,%esi


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