[v5.15] Internal error in timerfd_read

[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=16bf75bc580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=3f83fe607740b0f826e8
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+3f83fe...@syzkaller.appspotmail.com

Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 4169 Comm: syz.4.5 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 : timerfd_read+0x5d4/0x730 fs/timerfd.c:316
lr : __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:244 [inline]
lr : timerfd_read+0x5b4/0x730 fs/timerfd.c:316
sp : ffff80001fcd79c0
x29: ffff80001fcd7a80 x28: dfff800000000000 x27: ffff700003f9af3c
x26: 00000000200000c0 x25: 0000000000989680 x24: ffff0000eaba40e4
x23: ffff0000eaba40d8 x22: 0000000000000001 x21: 0000000000400140
x20: 0000000000000001 x19: 00000000fffffff2 x18: 0000000000000002
x17: 0000000040000000 x16: ffff800008a05628 x15: 0000000000000002
x14: 0000000000ff0100 x13: 1ffff0000282e06b x12: 0000000000080000
x11: 00000000000006a5 x10: 00000000200000c0 x9 : 0000ffffffffffff
x8 : 00000000200000c0 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
timerfd_read+0x5d4/0x730 fs/timerfd.c:316
vfs_read+0x278/0xa10 fs/read_write.c:483
ksys_read+0x120/0x210 fs/read_write.c:623
__do_sys_read fs/read_write.c:633 [inline]
__se_sys_read fs/read_write.c:631 [inline]
__arm64_sys_read+0x7c/0x90 fs/read_write.c:631
__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 f8000956 (2a1303e1)
---[ end trace 6c4294ddacf05c63 ]---
----------------
Code disassembly (best guess):
0: d503229f csdb
4: 2a1f03f3 mov w19, wzr
8: 2a1f03e0 mov w0, wzr
c: f8000956 sttr x22, [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=1210aaf0580000

kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=3f83fe607740b0f826e8
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=1705e842580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1386a5a2580000

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+3f83fe...@syzkaller.appspotmail.com

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

CPU: 1 PID: 4226 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 : timerfd_read+0x5d4/0x730 fs/timerfd.c:316
lr : __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:244 [inline]
lr : timerfd_read+0x5b4/0x730 fs/timerfd.c:316

sp : ffff80001f7c79c0
x29: ffff80001f7c7a80 x28: dfff800000000000 x27: ffff700003ef8f3c
x26: 0000000020000140 x25: 0000000000000005 x24: ffff0000ecb010e4
x23: ffff0000ecb010d8 x22: 0000000201ed6b2a x21: 0000000000400140
x20: 0000000000000001 x19: 00000000fffffff2 x18: 0000000000000003
x17: 0000000000000000 x16: ffff800008a05628 x15: 0000000000000003
x14: 0000000000ff0100 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000000020000140 x9 : 0000ffffffffffff
x8 : 0000000020000140 x7 : ffff800008750ed4 x6 : 0000000000000000

x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
timerfd_read+0x5d4/0x730 fs/timerfd.c:316
vfs_read+0x278/0xa10 fs/read_write.c:483
ksys_read+0x120/0x210 fs/read_write.c:623
__do_sys_read fs/read_write.c:633 [inline]
__se_sys_read fs/read_write.c:631 [inline]
__arm64_sys_read+0x7c/0x90 fs/read_write.c:631
__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 f8000956 (2a1303e1)

---[ end trace 508172c16cad07e2 ]---

----------------
Code disassembly (best guess):
0: d503229f csdb
4: 2a1f03f3 mov w19, wzr
8: 2a1f03e0 mov w0, wzr
c: f8000956 sttr x22, [x10]
* 10: 2a1303e1 mov w1, w19 <-- trapping instruction


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