[v5.15] Internal error in filldir64

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c79648372d02 Linux 5.15.189
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11c161a2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=aa37a094044d28d9ffbf
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7ab49562317a/disk-c7964837.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e847ec1e38d3/vmlinux-c7964837.xz
kernel image: https://storage.googleapis.com/syzbot-assets/263158c6371c/Image-c7964837.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+aa37a0...@syzkaller.appspotmail.com

Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 5237 Comm: syz.2.479 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 42400405 (nZcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=jc)
pc : filldir64+0x37c/0x9e4 fs/readdir.c:335
lr : filldir64+0x358/0x9e4 fs/readdir.c:335
sp : ffff8000200979f0
x29: ffff800020097a60 x28: 0000000000000008 x27: 0000000000000800
x26: ffff800020097cb8 x25: 0000000000007ca9 x24: 0000000000000000
x23: 0000000000000001 x22: ffff8000113e6840 x21: dfff800000000000
x20: 0000000000400040 x19: 00000000fffffff2 x18: 0000000000000000
x17: 0000000000000002 x16: ffff800008925a48 x15: 0000000000000001
x14: 0000000000ff0100 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000000000000008 x9 : 0000ffffffffffff
x8 : 0000000000000008 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
filldir64+0x37c/0x9e4 fs/readdir.c:335
dir_emit_dot include/linux/fs.h:3717 [inline]
dir_emit_dots include/linux/fs.h:3728 [inline]
proc_readfd_common+0x1b4/0x798 fs/proc/fd.c:250
proc_readfd+0x30/0x40 fs/proc/fd.c:284
iterate_dir+0x1f0/0x4cc fs/readdir.c:-1
__do_sys_getdents64 fs/readdir.c:369 [inline]
__se_sys_getdents64 fs/readdir.c:354 [inline]
__arm64_sys_getdents64+0x11c/0x340 fs/readdir.c:354
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: d503229f 2a1f03f3 2a1f03e0 f8000958 (2a1303e1)
---[ end trace 6709aaf5d429e4f8 ]---
----------------
Code disassembly (best guess):
0: d503229f csdb
4: 2a1f03f3 mov w19, wzr
8: 2a1f03e0 mov w0, wzr
c: f8000958 sttr x24, [x10]
* 10: 2a1303e1 mov w1, w19 <-- trapping instruction


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: c79648372d02 Linux 5.15.189
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=115db1a2580000

kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=aa37a094044d28d9ffbf
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=124f0842580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=146e49a2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7ab49562317a/disk-c7964837.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e847ec1e38d3/vmlinux-c7964837.xz
kernel image: https://storage.googleapis.com/syzbot-assets/263158c6371c/Image-c7964837.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+aa37a0...@syzkaller.appspotmail.com

Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:

CPU: 0 PID: 4227 Comm: syz.0.17 Not tainted 5.15.189-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 42400405 (nZcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=jc)
pc : filldir64+0x37c/0x9e4 fs/readdir.c:335
lr : filldir64+0x358/0x9e4 fs/readdir.c:335

sp : ffff80001fc279f0
x29: ffff80001fc27a60 x28: 0000000000000008 x27: 0000000000000800
x26: ffff80001fc27cb8 x25: 0000000000006654 x24: 0000000000000000

x23: 0000000000000001 x22: ffff8000113e6840 x21: dfff800000000000
x20: 0000000000400040 x19: 00000000fffffff2 x18: 0000000000000000

x17: ffff800016d04000 x16: ffff800008925a48 x15: ffff8000167e4500
x14: ffff0000dd3c5bc0 x13: dfff800000000000 x12: 0000000000ff0100

x11: 0000000000000000 x10: 0000000000000008 x9 : 0000ffffffffffff

x8 : 0000000000000008 x7 : 0000000000000000 x6 : 0000000000000000
x5 : ffff800016ea5968 x4 : 0000000000000002 x3 : ffff8000082bfb8c
x2 : 0000000000000001 x1 : 0000000000000001 x0 : 0000000000000000

Call trace:
filldir64+0x37c/0x9e4 fs/readdir.c:335
dir_emit_dot include/linux/fs.h:3717 [inline]
dir_emit_dots include/linux/fs.h:3728 [inline]
proc_readfd_common+0x1b4/0x798 fs/proc/fd.c:250
proc_readfd+0x30/0x40 fs/proc/fd.c:284
iterate_dir+0x1f0/0x4cc fs/readdir.c:-1
__do_sys_getdents64 fs/readdir.c:369 [inline]
__se_sys_getdents64 fs/readdir.c:354 [inline]
__arm64_sys_getdents64+0x11c/0x340 fs/readdir.c:354
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: d503229f 2a1f03f3 2a1f03e0 f8000958 (2a1303e1)

---[ end trace de8fc1a91c8198f9 ]---

----------------
Code disassembly (best guess):
0: d503229f csdb
4: 2a1f03f3 mov w19, wzr
8: 2a1f03e0 mov w0, wzr
c: f8000958 sttr x24, [x10]
* 10: 2a1303e1 mov w1, w19 <-- trapping instruction


---

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