syzbot


Internal error in mm_release

Status: upstream: reported C repro on 2025/08/13 04:01
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+7ee4651d2db83a5b6a2b@syzkaller.appspotmail.com
First crash: 4d12h, last: 3d07h
Bug presence (2)
Date Name Commit Repro Result
2025/08/14 linux-5.15.y (ToT) c79648372d02 C [report] Internal error in mm_release
2025/08/14 upstream (ToT) 0cc53520e68b C Didn't crash
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 general protection fault in mm_release 2 1 1578d 1578d 0/1 auto-closed as invalid on 2021/08/20 06:21

Sample crash report:
Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 4233 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 : mm_release+0x1c8/0x314 kernel/fork.c:1415
lr : __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:244 [inline]
lr : mm_release+0x1ac/0x314 kernel/fork.c:1414
sp : ffff80001fd877f0
x29: ffff80001fd877f0 x28: dfff800000000000 x27: ffff0000d4302370
x26: 0000000000400444 x25: 0000002000018000 x24: 1fffe0001a860434
x23: dfff800000000000 x22: 0000000020000180 x21: 0000000000000001
x20: ffff0000d43021a0 x19: ffff0000d4301b40 x18: 0000000000000000
x17: 0000000000000000 x16: ffff80000817ac7c x15: 00000000fffffe00
x14: 0000000000ff0100 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000020000180 x10: 0000ffffffffffff x9 : 0000000020000180
x8 : 00000000fffffff2 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
 mm_release+0x1c8/0x314 kernel/fork.c:1414
 exit_mm_release+0x30/0x40 kernel/fork.c:1432
 exit_mm+0xa4/0x684 kernel/exit.c:488
 do_exit+0x4ec/0x1f58 kernel/exit.c:870
 do_group_exit+0x100/0x268 kernel/exit.c:997
 get_signal+0x73c/0x1340 kernel/signal.c:2900
 do_signal arch/arm64/kernel/signal.c:893 [inline]
 do_notify_resume+0x35c/0x3128 arch/arm64/kernel/signal.c:946
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
 el0_svc+0xf0/0x1e0 arch/arm64/kernel/entry-common.c:609
 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: ea2a013f 9a9f02cb d503229f b8000968 (38776b08) 
---[ end trace 6a146c196bbf1d03 ]---
----------------
Code disassembly (best guess):
   0:	ea2a013f 	bics	xzr, x9, x10
   4:	9a9f02cb 	csel	x11, x22, xzr, eq	// eq = none
   8:	d503229f 	csdb
   c:	b8000968 	sttr	w8, [x11]
* 10:	38776b08 	ldrb	w8, [x24, x23] <-- trapping instruction

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/13 15:35 linux-5.15.y c79648372d02 22ec1469 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in mm_release
2025/08/13 04:01 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in mm_release
2025/08/13 04:00 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in mm_release
* Struck through repros no longer work on HEAD.