Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Write in sco_sock_timeout
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline]
BUG: KASAN: slab-use-after-free in __refcount_add include/linux/refcount.h:184 [inline]
BUG: KASAN: slab-use-after-free in __refcount_inc include/linux/refcount.h:241 [inline]
BUG: KASAN: slab-use-after-free in refcount_inc include/linux/refcount.h:258 [inline]
BUG: KASAN: slab-use-after-free in sock_hold include/net/sock.h:781 [inline]
BUG: KASAN: slab-use-after-free in sco_sock_timeout+0x8b/0x270 net/bluetooth/sco.c:92
Write of size 4 at addr ffff88807e2d5080 by task kworker/1:1/47
CPU: 1 UID: 0 PID: 47 Comm: kworker/1:1 Not tainted 6.12.0-rc1-syzkaller-ge32cde8d2bd7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events sco_sock_timeout
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline]
__refcount_add include/linux/refcount.h:184 [inline]
__refcount_inc include/linux/refcount.h:241 [inline]
refcount_inc include/linux/refcount.h:258 [inline]
sock_hold include/net/sock.h:781 [inline]
sco_sock_timeout+0x8b/0x270 net/bluetooth/sco.c:92
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310
worker_thread+0x870/0xd30 kernel/workqueue.c:3391
kthread+0x2f2/0x390 kernel/kthread.c:389
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Allocated by task 5759:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:257 [inline]
__do_kmalloc_node mm/slub.c:4265 [inline]
__kmalloc_noprof+0x1fc/0x400 mm/slub.c:4277
kmalloc_noprof include/linux/slab.h:882 [inline]
sk_prot_alloc+0xe0/0x210 net/core/sock.c:2164
sk_alloc+0x38/0x370 net/core/sock.c:2217
bt_sock_alloc+0x3c/0x340 net/bluetooth/af_bluetooth.c:148
sco_sock_alloc net/bluetooth/sco.c:500 [inline]
sco_sock_create+0xbb/0x390 net/bluetooth/sco.c:531
bt_sock_create+0x163/0x230 net/bluetooth/af_bluetooth.c:132
__sock_create+0x492/0x920 net/socket.c:1576
sock_create net/socket.c:1627 [inline]
__sys_socket_create net/socket.c:1664 [inline]
__sys_socket+0x150/0x3c0 net/socket.c:1711
__do_sys_socket net/socket.c:1725 [inline]
__se_sys_socket net/socket.c:1723 [inline]
__x64_sys_socket+0x7a/0x90 net/socket.c:1723
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 5760:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:2343 [inline]
slab_free mm/slub.c:4580 [inline]
kfree+0x1a0/0x440 mm/slub.c:4728
sk_prot_free net/core/sock.c:2200 [inline]
__sk_destruct+0x479/0x5f0 net/core/sock.c:2292
sco_sock_release+0x25e/0x320 net/bluetooth/sco.c:1259
__sock_release net/socket.c:658 [inline]
sock_close+0xbe/0x240 net/socket.c:1426
__fput+0x241/0x880 fs/file_table.c:431
task_work_run+0x251/0x310 kernel/task_work.c:228
get_signal+0x15e8/0x1740 kernel/signal.c:2690
arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218
do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88807e2d5000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 128 bytes inside of
freed 2048-byte region [ffff88807e2d5000, ffff88807e2d5800)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7e2d0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff888015442000 ffffea0000a07800 dead000000000002
raw: 0000000000000000 0000000000080008 00000001f5000000 0000000000000000
head: 00fff00000000040 ffff888015442000 ffffea0000a07800 dead000000000002
head: 0000000000000000 0000000000080008 00000001f5000000 0000000000000000
head: 00fff00000000003 ffffea0001f8b401 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4533, tgid 4533 (acpid), ts 19751533769, free_ts 17515017965
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1537
prep_new_page mm/page_alloc.c:1545 [inline]
get_page_from_freelist+0x3045/0x3190 mm/page_alloc.c:3457
__alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4733
alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
alloc_slab_page+0x6a/0x120 mm/slub.c:2413
allocate_slab+0x5a/0x2f0 mm/slub.c:2579
new_slab mm/slub.c:2632 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3819
__slab_alloc+0x58/0xa0 mm/slub.c:3909
__slab_alloc_node mm/slub.c:3962 [inline]
slab_alloc_node mm/slub.c:4123 [inline]
__do_kmalloc_node mm/slub.c:4264 [inline]
__kmalloc_noprof+0x25a/0x400 mm/slub.c:4277
kmalloc_noprof include/linux/slab.h:882 [inline]
sk_prot_alloc+0xe0/0x210 net/core/sock.c:2164
sk_alloc+0x38/0x370 net/core/sock.c:2217
__netlink_create+0x65/0x260 net/netlink/af_netlink.c:646
netlink_create+0x3ab/0x560 net/netlink/af_netlink.c:704
__sock_create+0x492/0x920 net/socket.c:1576
sock_create net/socket.c:1627 [inline]
__sys_socket_create net/socket.c:1664 [inline]
__sys_socket+0x150/0x3c0 net/socket.c:1711
__do_sys_socket net/socket.c:1725 [inline]
__se_sys_socket net/socket.c:1723 [inline]
__x64_sys_socket+0x7a/0x90 net/socket.c:1723
page last free pid 1 tgid 1 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1108 [inline]
free_unref_page+0xcfb/0xf20 mm/page_alloc.c:2638
free_contig_range+0x152/0x550 mm/page_alloc.c:6748
destroy_args+0x8a/0x840 mm/debug_vm_pgtable.c:1017
debug_vm_pgtable+0x4be/0x550 mm/debug_vm_pgtable.c:1397
do_one_initcall+0x24a/0x880 init/main.c:1269
do_initcall_level+0x157/0x210 init/main.c:1331
do_initcalls+0x3f/0x80 init/main.c:1347
kernel_init_freeable+0x435/0x5d0 init/main.c:1580
kernel_init+0x1d/0x2b0 init/main.c:1469
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Memory state around the buggy address:
ffff88807e2d4f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807e2d5000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807e2d5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807e2d5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807e2d5180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Tested on:
commit: e32cde8d Merge tag 'sched_ext-for-6.12-rc1-fixes-1' of..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=174f23d0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5997f8b13c390e73
dashboard link: https://syzkaller.appspot.com/bug?extid=4c0d0c4cde787116d465
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
Note: no patches were applied.
