[v5.15] Internal error in fault_in_readable

[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=121e41a2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=50b078eef00f85a3afd9
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+50b078...@syzkaller.appspotmail.com

Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 4716 Comm: syz.0.229 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 : fault_in_readable+0x138/0x354 mm/gup.c:1793
lr : fault_in_readable+0x114/0x354 mm/gup.c:1793
sp : ffff800020087570
x29: ffff800020087590 x28: ffff0000c89b1b40 x27: 0000000000000fc9
x26: 0000000000000000 x25: dfff800000000000 x24: 0000000000020002
x23: 0000000000000fc9 x22: ffff0000c89b1b64 x21: 00000000fffffff2
x20: 0000000000000000 x19: 0000000002000200 x18: 0000000000000000
x17: 0000000000000002 x16: ffff800008733c60 x15: 0000000020000100
x14: 0000000000ff0100 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000000000020002 x9 : 0000ffffffffffff
x8 : 0000000000000000 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
fault_in_readable+0x138/0x354 mm/gup.c:1793
fault_in_iov_iter_readable+0x120/0x248 lib/iov_iter.c:460
generic_perform_write+0x14c/0x480 mm/filemap.c:3775
__generic_file_write_iter+0x23c/0x454 mm/filemap.c:3912
blkdev_write_iter+0x2f8/0x44c block/fops.c:537
do_iter_readv_writev+0x3a0/0x4f8 fs/read_write.c:-1
do_iter_write+0x1c4/0x670 fs/read_write.c:855
vfs_writev fs/read_write.c:928 [inline]
do_writev+0x1e0/0x380 fs/read_write.c:971
__do_sys_writev fs/read_write.c:1044 [inline]
__se_sys_writev fs/read_write.c:1041 [inline]
__arm64_sys_writev+0x80/0x94 fs/read_write.c:1041
__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 381f83bf 2a1f03f5 38400948 (381f83a8)
---[ end trace 134b7c846348edbf ]---
----------------
Code disassembly (best guess):
0: d503229f csdb
4: 381f83bf sturb wzr, [x29, #-8]
8: 2a1f03f5 mov w21, wzr
c: 38400948 ldtrb w8, [x10]
* 10: 381f83a8 sturb w8, [x29, #-8] <-- 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=1560a9a2580000

kernel config: https://syzkaller.appspot.com/x/.config?x=9e47345638b85bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=50b078eef00f85a3afd9
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=17184842580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13ea0af0580000

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+50b078...@syzkaller.appspotmail.com

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

CPU: 0 PID: 4192 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 : fault_in_readable+0x26c/0x354 mm/gup.c:1801
lr : fault_in_readable+0x248/0x354 mm/gup.c:1801
sp : ffff80001fdc77f0
x29: ffff80001fdc7810 x28: 0000000000000000 x27: 0000000000001000
x26: 0000000000000000 x25: 0000000000000000 x24: 00000000fffffff2
x23: 1fffe0001af926d0 x22: ffff0000d7c93680 x21: 0000000000000000
x20: 0000000000000000 x19: dfff800000000000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff800008733d94 x15: 0000000000000000
x14: 0000000000000000 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000

x8 : 0000000000000000 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:

fault_in_readable+0x26c/0x354 mm/gup.c:1801

fault_in_iov_iter_readable+0x120/0x248 lib/iov_iter.c:460
generic_perform_write+0x14c/0x480 mm/filemap.c:3775
__generic_file_write_iter+0x23c/0x454 mm/filemap.c:3912

generic_file_write_iter+0xb0/0x1b4 mm/filemap.c:3944
call_write_iter include/linux/fs.h:2172 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x7c8/0xa2c fs/read_write.c:594
ksys_write+0x120/0x210 fs/read_write.c:647
__do_sys_write fs/read_write.c:659 [inline]
__se_sys_write fs/read_write.c:656 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:656

__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: 381f43b5 2a1503f8 2a1503e0 38400909 (381f43a9)
---[ end trace 59644166efa01e09 ]---

----------------
Code disassembly (best guess):

0: 381f43b5 sturb w21, [x29, #-12]
4: 2a1503f8 mov w24, w21
8: 2a1503e0 mov w0, w21
c: 38400909 ldtrb w9, [x8]
* 10: 381f43a9 sturb w9, [x29, #-12] <-- trapping instruction


---
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