KASAN: use-after-free Read in ring_buffer_peek

Status: upstream: reported C repro on 2026/08/16 22:10
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+685955db58555575fdd2@syzkaller.appspotmail.com
First crash: 5d08h, last: 5d08h
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
8832a07d assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: use-after-free Read in ring_buffer_peek 2026/08/12 22:05 2026/08/12 22:05 2026/08/12 22:36 a56bc0a5
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH] tracing: Fix use-after-free in trace_pipe read on sub-buffer order change 1 (1) 2026/08/17 14:06
[syzbot] KASAN: use-after-free Read in ring_buffer_peek 0 (2) 2026/08/17 05:03
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 KASAN: slab-out-of-bounds Read in ring_buffer_peek 19 8 1d20h 18d 0/2 premoderation: reported on 2026/07/30 09:52
android-5-15 KASAN: use-after-free Read in ring_buffer_peek origin:lts 19 syz, C 12 12h47m 18d 0/2 upstream: reported C repro on 2026/07/30 13:32
android-5-10 KASAN: use-after-free Read in ring_buffer_peek 19 10 3d07h 15d 0/2 premoderation: reported on 2026/08/02 07:28
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/08/17 05:03 18m kartikey406@gmail.com patch upstream OK job log log

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in ring_buffer_peek+0x3e0/0x430 kernel/trace/ring_buffer.c:6274
Read of size 1 at addr ffff88802a4cf010 by task syz-executor989/6002

CPU: 1 UID: 0 PID: 6002 Comm: syz-executor989 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 ring_buffer_peek+0x3e0/0x430 kernel/trace/ring_buffer.c:6274
 peek_next_entry+0x17a/0x250 kernel/trace/trace.c:2354
 __find_next_entry+0x1ed/0x4e0 kernel/trace/trace.c:2398
 trace_find_next_entry_inc+0x3d/0x1c0 kernel/trace/trace.c:2672
 tracing_read_pipe+0x557/0xd60 kernel/trace/trace.c:5440
 vfs_read+0x1e4/0xb40 fs/read_write.c:572
 ksys_read+0x12a/0x250 fs/read_write.c:716
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f588d3b7d9e
Code: 08 0f 85 f5 e2 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08
RSP: 002b:00007f588d361198 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f588d3626c0 RCX: 00007f588d3b7d9e
RDX: 0000000000001000 RSI: 00007f588d361200 RDI: 0000000000000003
RBP: 00007f588d361200 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffd0
R13: 0000000000000000 R14: 00007ffe1b5bf5a0 R15: 00007ffe1b5bf688
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a4cf
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001ddbd08 ffffea00006f0fc8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x44dc0(GFP_KERNEL|__GFP_ZERO|__GFP_RETRY_MAYFAIL|__GFP_COMP), pid 5981, tgid 5981 (syz-executor989), ts 130836230668, free_ts 170720200085
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 __alloc_pages_noprof+0xb/0x110 mm/page_alloc.c:5338
 __alloc_pages_node_noprof include/linux/gfp.h:291 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:318 [inline]
 alloc_cpu_data+0x60/0x160 kernel/trace/ring_buffer.c:427
 __rb_allocate_pages+0xbd5/0x10a0 kernel/trace/ring_buffer.c:2436
 ring_buffer_resize+0x6df/0x1e80 kernel/trace/ring_buffer.c:3274
 __tracing_resize_ring_buffer.part.0+0x52/0x1f0 kernel/trace/trace.c:4738
 __tracing_resize_ring_buffer kernel/trace/trace.c:4732 [inline]
 tracing_update_buffers+0xd4/0xf0 kernel/trace/trace.c:4977
 system_enable_write+0x151/0x300 kernel/trace/trace_events.c:2020
 vfs_write+0x2aa/0x1050 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 6003 tgid 5981 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 free_buffer_page kernel/trace/ring_buffer.c:398 [inline]
 ring_buffer_subbuf_order_set+0x1325/0x18e0 kernel/trace/ring_buffer.c:7444
 buffer_subbuf_size_write+0x182/0x280 kernel/trace/trace.c:8221
 vfs_write+0x2aa/0x1050 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802a4cef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88802a4cef80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
>ffff88802a4cf000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff88802a4cf080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88802a4cf100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
==================================================================
BUG: KASAN: use-after-free in ring_buffer_event_length+0x218/0x260 kernel/trace/ring_buffer.c:266
Read of size 4 at addr ffff88802a4cf010 by task syz-executor989/6002

CPU: 0 UID: 0 PID: 6002 Comm: syz-executor989 Tainted: G    B               syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 ring_buffer_event_length+0x218/0x260 kernel/trace/ring_buffer.c:266
 peek_next_entry+0x198/0x250 kernel/trace/trace.c:2359
 __find_next_entry+0x1ed/0x4e0 kernel/trace/trace.c:2398
 trace_find_next_entry_inc+0x3d/0x1c0 kernel/trace/trace.c:2672
 tracing_read_pipe+0x557/0xd60 kernel/trace/trace.c:5440
 vfs_read+0x1e4/0xb40 fs/read_write.c:572
 ksys_read+0x12a/0x250 fs/read_write.c:716
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f588d3b7d9e
Code: 08 0f 85 f5 e2 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08
RSP: 002b:00007f588d361198 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f588d3626c0 RCX: 00007f588d3b7d9e
RDX: 0000000000001000 RSI: 00007f588d361200 RDI: 0000000000000003
RBP: 00007f588d361200 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffd0
R13: 0000000000000000 R14: 00007ffe1b5bf5a0 R15: 00007ffe1b5bf688
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a4cf
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001ddbd08 ffffea00006f0fc8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x44dc0(GFP_KERNEL|__GFP_ZERO|__GFP_RETRY_MAYFAIL|__GFP_COMP), pid 5981, tgid 5981 (syz-executor989), ts 130836230668, free_ts 170720200085
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 __alloc_pages_noprof+0xb/0x110 mm/page_alloc.c:5338
 __alloc_pages_node_noprof include/linux/gfp.h:291 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:318 [inline]
 alloc_cpu_data+0x60/0x160 kernel/trace/ring_buffer.c:427
 __rb_allocate_pages+0xbd5/0x10a0 kernel/trace/ring_buffer.c:2436
 ring_buffer_resize+0x6df/0x1e80 kernel/trace/ring_buffer.c:3274
 __tracing_resize_ring_buffer.part.0+0x52/0x1f0 kernel/trace/trace.c:4738
 __tracing_resize_ring_buffer kernel/trace/trace.c:4732 [inline]
 tracing_update_buffers+0xd4/0xf0 kernel/trace/trace.c:4977
 system_enable_write+0x151/0x300 kernel/trace/trace_events.c:2020
 vfs_write+0x2aa/0x1050 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 6003 tgid 5981 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 free_buffer_page kernel/trace/ring_buffer.c:398 [inline]
 ring_buffer_subbuf_order_set+0x1325/0x18e0 kernel/trace/ring_buffer.c:7444
 buffer_subbuf_size_write+0x182/0x280 kernel/trace/trace.c:8221
 vfs_write+0x2aa/0x1050 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802a4cef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88802a4cef80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
>ffff88802a4cf000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff88802a4cf080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88802a4cf100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
==================================================================
BUG: KASAN: use-after-free in rb_event_data_length kernel/trace/ring_buffer.c:198 [inline]
BUG: KASAN: use-after-free in rb_event_length kernel/trace/ring_buffer.c:227 [inline]
BUG: KASAN: use-after-free in ring_buffer_event_length+0x243/0x260 kernel/trace/ring_buffer.c:269
Read of size 1 at addr ffff88802a4cf010 by task syz-executor989/6002

CPU: 0 UID: 0 PID: 6002 Comm: syz-executor989 Tainted: G    B               syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 rb_event_data_length kernel/trace/ring_buffer.c:198 [inline]
 rb_event_length kernel/trace/ring_buffer.c:227 [inline]
 ring_buffer_event_length+0x243/0x260 kernel/trace/ring_buffer.c:269
 peek_next_entry+0x198/0x250 kernel/trace/trace.c:2359
 __find_next_entry+0x1ed/0x4e0 kernel/trace/trace.c:2398
 trace_find_next_entry_inc+0x3d/0x1c0 kernel/trace/trace.c:2672
 tracing_read_pipe+0x557/0xd60 kernel/trace/trace.c:5440
 vfs_read+0x1e4/0xb40 fs/read_write.c:572
 ksys_read+0x12a/0x250 fs/read_write.c:716
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f588d3b7d9e
Code: 08 0f 85 f5 e2 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08
RSP: 002b:00007f588d361198 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f588d3626c0 RCX: 00007f588d3b7d9e
RDX: 0000000000001000 RSI: 00007f588d361200 RDI: 0000000000000003
RBP: 00007f588d361200 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffd0
R13: 0000000000000000 R14: 00007ffe1b5bf5a0 R15: 00007ffe1b5bf688
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a4cf
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001ddbd08 ffffea00006f0fc8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x44dc0(GFP_KERNEL|__GFP_ZERO|__GFP_RETRY_MAYFAIL|__GFP_COMP), pid 5981, tgid 5981 (syz-executor989), ts 130836230668, free_ts 170720200085
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 __alloc_pages_noprof+0xb/0x110 mm/page_alloc.c:5338
 __alloc_pages_node_noprof include/linux/gfp.h:291 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:318 [inline]
 alloc_cpu_data+0x60/0x160 kernel/trace/ring_buffer.c:427
 __rb_allocate_pages+0xbd5/0x10a0 kernel/trace/ring_buffer.c:2436
 ring_buffer_resize+0x6df/0x1e80 kernel/trace/ring_buffer.c:3274
 __tracing_resize_ring_buffer.part.0+0x52/0x1f0 kernel/trace/trace.c:4738
 __tracing_resize_ring_buffer kernel/trace/trace.c:4732 [inline]
 tracing_update_buffers+0xd4/0xf0 kernel/trace/trace.c:4977
 system_enable_write+0x151/0x300 kernel/trace/trace_events.c:2020
 vfs_write+0x2aa/0x1050 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 6003 tgid 5981 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 free_buffer_page kernel/trace/ring_buffer.c:398 [inline]
 ring_buffer_subbuf_order_set+0x1325/0x18e0 kernel/trace/ring_buffer.c:7444
 buffer_subbuf_size_write+0x182/0x280 kernel/trace/trace.c:8221
 vfs_write+0x2aa/0x1050 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802a4cef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88802a4cef80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
>ffff88802a4cf000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff88802a4cf080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88802a4cf100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
==================================================================
BUG: KASAN: use-after-free in rb_event_data kernel/trace/ring_buffer.c:284 [inline]
BUG: KASAN: use-after-free in ring_buffer_event_data+0x129/0x150 kernel/trace/ring_buffer.c:300
Read of size 4 at addr ffff88802a4cf010 by task syz-executor989/6002

CPU: 1 UID: 0 PID: 6002 Comm: syz-executor989 Tainted: G    B               syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 rb_event_data kernel/trace/ring_buffer.c:284 [inline]
 ring_buffer_event_data+0x129/0x150 kernel/trace/ring_buffer.c:300
 peek_next_entry+0x1d3/0x250 kernel/trace/trace.c:2360
 __find_next_entry+0x1ed/0x4e0 kernel/trace/trace.c:2398
 trace_find_next_entry_inc+0x3d/0x1c0 kernel/trace/trace.c:2672
 tracing_read_pipe+0x557/0xd60 kernel/trace/trace.c:5440
 vfs_read+0x1e4/0xb40 fs/read_write.c:572
 ksys_read+0x12a/0x250 fs/read_write.c:716
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f588d3b7d9e
Code: 08 0f 85 f5 e2 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08
RSP: 002b:00007f588d361198 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f588d3626c0 RCX: 00007f588d3b7d9e
RDX: 0000000000001000 RSI: 00007f588d361200 RDI: 0000000000000003
RBP: 00007f588d361200 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffd0
R13: 0000000000000000 R14: 00007ffe1b5bf5a0 R15: 00007ffe1b5bf688
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a4cf
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001ddbd08 ffffea00006f0fc8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x44dc0(GFP_KERNEL|__GFP_ZERO|__GFP_RETRY_MAYFAIL|__GFP_COMP), pid 5981, tgid 5981 (syz-executor989), ts 130836230668, free_ts 170720200085
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 __alloc_pages_noprof+0xb/0x110 mm/page_alloc.c:5338
 __alloc_pages_node_noprof include/linux/gfp.h:291 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:318 [inline]
 alloc_cpu_data+0x60/0x160 kernel/trace/ring_buffer.c:427
 __rb_allocate_pages+0xbd5/0x10a0 kernel/trace/ring_buffer.c:2436
 ring_buffer_resize+0x6df/0x1e80 kernel/trace/ring_buffer.c:3274
 __tracing_resize_ring_buffer.part.0+0x52/0x1f0 kernel/trace/trace.c:4738
 __tracing_resize_ring_buffer kernel/trace/trace.c:4732 [inline]
 tracing_update_buffers+0xd4/0xf0 kernel/trace/trace.c:4977
 system_enable_write+0x151/0x300 kernel/trace/trace_events.c:2020
 vfs_write+0x2aa/0x1050 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 6003 tgid 5981 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 free_buffer_page kernel/trace/ring_buffer.c:398 [inline]
 ring_buffer_subbuf_order_set+0x1325/0x18e0 kernel/trace/ring_buffer.c:7444
 buffer_subbuf_size_write+0x182/0x280 kernel/trace/trace.c:8221
 vfs_write+0x2aa/0x1050 fs/read_write.c:685
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802a4cef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88802a4cef80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
>ffff88802a4cf000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff88802a4cf080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88802a4cf100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/12 22:05 upstream 3d6d817622b0 aaffb173 .config console log report C ci-upstream-kasan-badwrites-root KASAN: use-after-free Read in ring_buffer_peek
* Struck through repros no longer work on HEAD.