[Android 5.10] KASAN: use-after-free Read in ring_buffer_peek

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f61a392235e0 Merge 5.10.272 into android13-5.10-lts
git tree: android13-5.10-lts
console output: https://syzkaller.appspot.com/x/log.txt?x=17d5be2d580000
kernel config: https://syzkaller.appspot.com/x/.config?x=40fa24cc6888ca30
dashboard link: https://syzkaller.appspot.com/bug?extid=b6b65ba365b8f02f5972
compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14f29cdd580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14de3df1580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1067764b73c1/disk-f61a3922.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/eda1b07ee362/vmlinux-f61a3922.xz
kernel image: https://storage.googleapis.com/syzbot-assets/109d1701bea2/bzImage-f61a3922.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b6b65b...@syzkaller.appspotmail.com

RDX: 0000000000000001 RSI: 0000200000000b80 RDI: 0000000000000003
RBP: 00007f37372bcaf8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f37374aafac R14: 00007f37374aafa0 R15: 00007f37374aafa0
---[ end trace 5c47629c180235d3 ]---
==================================================================
BUG: KASAN: use-after-free in rb_buffer_peek+0x71a/0x7a0 kernel/trace/ring_buffer.c:4568
Read of size 4 at addr ffff88818606b221 by task syz.5.62/434

CPU: 1 PID: 434 Comm: syz.5.62 Tainted: G W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
__dump_stack+0x21/0x24 lib/dump_stack.c:77
dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118
print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:435 [inline]
kasan_report+0x100/0x140 mm/kasan/report.c:452
__asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
rb_buffer_peek+0x71a/0x7a0 kernel/trace/ring_buffer.c:4568
ring_buffer_peek+0x183/0x360 kernel/trace/ring_buffer.c:4762
peek_next_entry kernel/trace/trace.c:3495 [inline]
__find_next_entry+0x34d/0x6b0 kernel/trace/trace.c:3539
trace_find_next_entry_inc kernel/trace/trace.c:3619 [inline]
tracing_read_pipe+0x3b8/0xab0 kernel/trace/trace.c:6410
do_loop_readv_writev include/linux/uio.h:-1 [inline]
do_iter_read+0x3e9/0x5d0 fs/read_write.c:803
vfs_readv fs/read_write.c:921 [inline]
do_readv+0x25d/0x450 fs/read_write.c:958
__do_sys_readv fs/read_write.c:1049 [inline]
__se_sys_readv fs/read_write.c:1046 [inline]
__x64_sys_readv+0x7d/0x90 fs/read_write.c:1046
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f3737224b19
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff628ce9f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 00007f37374aafa0 RCX: 00007f3737224b19
RDX: 0000000000000001 RSI: 0000200000000b80 RDI: 0000000000000003
RBP: 00007f37372bcaf8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f37374aafac R14: 00007f37374aafa0 R15: 00007f37374aafa0

The buggy address belongs to the page:
page:ffffea0006181ac0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x18606b
flags: 0x4000000000000000()
raw: 4000000000000000 ffffea0006181ac8 ffffea0006181ac8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
ffff88818606b100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88818606b180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88818606b200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88818606b280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88818606b300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
------------[ cut here ]------------
WARNING: CPU: 1 PID: 434 at kernel/trace/ring_buffer.c:4349 arch_atomic_inc include/linux/instrumented.h:101 [inline]
WARNING: CPU: 1 PID: 434 at kernel/trace/ring_buffer.c:4349 atomic_inc include/asm-generic/atomic-instrumented.h:241 [inline]
WARNING: CPU: 1 PID: 434 at kernel/trace/ring_buffer.c:4349 rb_get_reader_page+0xa78/0xbf0 kernel/trace/ring_buffer.c:4348
Modules linked in:
CPU: 1 PID: 434 Comm: syz.5.62 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:rb_get_reader_page+0xa78/0xbf0 kernel/trace/ring_buffer.c:4348
Code: 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 ad 3d 38 00 48 8b 1b 48 8d 7b 08 be 04 00 00 00 e8 9c 3f 38 00 f0 ff 43 08 <0f> 0b 48 83 7c 24 20 00 75 91 e8 a9 af fd ff e9 45 fe ff ff e8 9f
RSP: 0018:ffffc900025778e0 EFLAGS: 00010002
RAX: 1ffff1102000aa01 RBX: ffff888100052600 RCX: ffffffff81670704
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff888100052608
RBP: ffffc90002577a58 R08: ffff88810005260b R09: 1ffff1102000a4c1
R10: dffffc0000000000 R11: ffffed102000a4c2 R12: 0000000086000211
R13: 1ffff1102000a123 R14: 1ffff1102000a126 R15: dffffc0000000000
FS: 000055558cd88500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33863fff CR3: 00000001120bb000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rb_buffer_peek+0x60/0x7a0 kernel/trace/ring_buffer.c:4562
ring_buffer_consume+0x1b2/0x350 kernel/trace/ring_buffer.c:4842
trace_consume kernel/trace/trace.c:3630 [inline]
tracing_read_pipe+0x599/0xab0 kernel/trace/trace.c:6434
do_loop_readv_writev include/linux/uio.h:-1 [inline]
do_iter_read+0x3e9/0x5d0 fs/read_write.c:803
vfs_readv fs/read_write.c:921 [inline]
do_readv+0x25d/0x450 fs/read_write.c:958
__do_sys_readv fs/read_write.c:1049 [inline]
__se_sys_readv fs/read_write.c:1046 [inline]
__x64_sys_readv+0x7d/0x90 fs/read_write.c:1046
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f3737224b19
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff628ce9f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 00007f37374aafa0 RCX: 00007f3737224b19
RDX: 0000000000000001 RSI: 0000200000000b80 RDI: 0000000000000003
RBP: 00007f37372bcaf8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f37374aafac R14: 00007f37374aafa0 R15: 00007f37374aafa0
---[ end trace 5c47629c180235d4 ]---
------------[ cut here ]------------
WARNING: CPU: 1 PID: 434 at kernel/trace/ring_buffer.c:4349 arch_atomic_inc include/linux/instrumented.h:101 [inline]
WARNING: CPU: 1 PID: 434 at kernel/trace/ring_buffer.c:4349 atomic_inc include/asm-generic/atomic-instrumented.h:241 [inline]
WARNING: CPU: 1 PID: 434 at kernel/trace/ring_buffer.c:4349 rb_get_reader_page+0xa78/0xbf0 kernel/trace/ring_buffer.c:4348
Modules linked in:
CPU: 1 PID: 434 Comm: syz.5.62 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:rb_get_reader_page+0xa78/0xbf0 kernel/trace/ring_buffer.c:4348
Code: 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 ad 3d 38 00 48 8b 1b 48 8d 7b 08 be 04 00 00 00 e8 9c 3f 38 00 f0 ff 43 08 <0f> 0b 48 83 7c 24 20 00 75 91 e8 a9 af fd ff e9 45 fe ff ff e8 9f
RSP: 0018:ffffc90002577900 EFLAGS: 00010006
RAX: 1ffff1102000aa01 RBX: ffff888100052600 RCX: ffffffff81670704
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff888100052608
RBP: ffffc90002577a68 R08: ffff88810005260b R09: 1ffff1102000a4c1
R10: dffffc0000000000 R11: ffffed102000a4c2 R12: 0000000086000211
R13: 1ffff1102000a123 R14: 1ffff1102000a126 R15: dffffc0000000000
FS: 000055558cd88500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33863fff CR3: 00000001120bb000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rb_advance_reader+0x2b/0x6b0 kernel/trace/ring_buffer.c:4490
ring_buffer_consume+0x1e6/0x350 kernel/trace/ring_buffer.c:4845
trace_consume kernel/trace/trace.c:3630 [inline]
tracing_read_pipe+0x599/0xab0 kernel/trace/trace.c:6434
do_loop_readv_writev include/linux/uio.h:-1 [inline]
do_iter_read+0x3e9/0x5d0 fs/read_write.c:803
vfs_readv fs/read_write.c:921 [inline]
do_readv+0x25d/0x450 fs/read_write.c:958
__do_sys_readv fs/read_write.c:1049 [inline]
__se_sys_readv fs/read_write.c:1046 [inline]
__x64_sys_readv+0x7d/0x90 fs/read_write.c:1046
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f3737224b19
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff628ce9f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 00007f37374aafa0 RCX: 00007f3737224b19
RDX: 0000000000000001 RSI: 0000200000000b80 RDI: 0000000000000003
RBP: 00007f37372bcaf8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f37374aafac R14: 00007f37374aafa0 R15: 00007f37374aafa0
---[ end trace 5c47629c180235d5 ]---


---
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