ci2 starts bisection 2025-05-23 02:08:10.972892351 +0000 UTC m=+7457.455900973
bisecting fixing commit since 7d1f9b5c2ff516f9c97fffe9613799b29ef4946d
building syzkaller on 1a5d9317ecfa21e32cf9c876306c7b5f665999bf
ensuring issue is reproducible on original commit 7d1f9b5c2ff516f9c97fffe9613799b29ef4946d

testing commit 7d1f9b5c2ff516f9c97fffe9613799b29ef4946d gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: 0dc268411dd55c89215e84ed40c22133d0231ee2de736bae70f9f2dbbdd48dfb
run #0: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #1: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #2: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #3: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #4: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #5: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #6: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #7: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #8: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #9: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #10: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #11: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #12: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #13: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #14: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #15: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #16: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #17: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #18: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #19: OK
representative crash: KASAN: use-after-free Write in l2tp_session_delete, types: [KASAN]
check whether we can drop unnecessary instrumentation
disabling configs for [BUG LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN], they are not needed
testing commit 7d1f9b5c2ff516f9c97fffe9613799b29ef4946d gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: 2a03e05c3b5c46ef362ca2474aeea7da9f43f08a6142a87af07a69b80029d30a
all runs: crashed: KASAN: use-after-free Write in l2tp_session_delete
representative crash: KASAN: use-after-free Write in l2tp_session_delete, types: [KASAN]
the bug reproduces without the instrumentation
disabling configs for [LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN BUG], they are not needed
kconfig minimization: base=4921 full=6215 leaves diff=255
split chunks (needed=false): <255>
split chunk #0 of len 255 into 5 parts
testing without sub-chunk 1/5
disabling configs for [LEAK UBSAN BUG LOCKDEP ATOMIC_SLEEP HANG], they are not needed
testing commit 7d1f9b5c2ff516f9c97fffe9613799b29ef4946d gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: fc854d01bc9e44047d7321a351434dc15e0fd4174f7b6b9a1cd8717e8923ec3d
run #0: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #1: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #2: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #3: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #4: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #5: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #6: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #7: OK
run #8: OK
run #9: OK
representative crash: KASAN: use-after-free Write in l2tp_session_delete, types: [KASAN]
the chunk can be dropped
testing without sub-chunk 2/5
disabling configs for [ATOMIC_SLEEP HANG LEAK UBSAN BUG LOCKDEP], they are not needed
testing commit 7d1f9b5c2ff516f9c97fffe9613799b29ef4946d gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: 907da957e25c2f2f6dc322e864690bee4c13d1fe7c733ee71b9979d7de76e52b
run #0: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #1: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #2: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #3: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #4: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #5: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #6: OK
run #7: OK
run #8: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #9: OK
representative crash: KASAN: use-after-free Write in l2tp_session_delete, types: [KASAN]
the chunk can be dropped
testing without sub-chunk 3/5
disabling configs for [HANG LEAK UBSAN BUG LOCKDEP ATOMIC_SLEEP], they are not needed
testing commit 7d1f9b5c2ff516f9c97fffe9613799b29ef4946d gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: 9c7ca3238d5c3cbdc0ad415e9ea456cea344eb06093dc9d34bdcd3f01e4592ee
run #0: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #1: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #2: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #3: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #4: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #5: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #6: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #7: OK
run #8: OK
run #9: OK
representative crash: KASAN: use-after-free Write in l2tp_session_delete, types: [KASAN]
the chunk can be dropped
testing without sub-chunk 4/5
disabling configs for [BUG LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN], they are not needed
testing commit 7d1f9b5c2ff516f9c97fffe9613799b29ef4946d gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: 576eb52659aaf5f132a67dc417e10e95ae052adc94788038248a7e941e2d011f
run #0: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #1: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #2: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #3: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #4: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #5: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #6: OK
run #7: OK
run #8: OK
run #9: OK
representative crash: KASAN: use-after-free Write in l2tp_session_delete, types: [KASAN]
the chunk can be dropped
testing without sub-chunk 5/5
disabling configs for [LOCKDEP ATOMIC_SLEEP HANG LEAK UBSAN BUG], they are not needed
testing commit 7d1f9b5c2ff516f9c97fffe9613799b29ef4946d gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40
failed building 7d1f9b5c2ff516f9c97fffe9613799b29ef4946d: net/socket.c:1191: undefined reference to `wext_handle_ioctl'
net/socket.c:3390: undefined reference to `compat_wext_handle_ioctl'
net/core/net-procfs.c:343: undefined reference to `wext_proc_exit'
net/core/net-procfs.c:327: undefined reference to `wext_proc_init'
minimized to 51 configs; suspects: [HID_ZEROPLUS USB_MON USB_NET_CDC_MBIM USB_NET_CDC_SUBSET USB_NET_CDC_SUBSET_ENABLE USB_NET_DM9601 USB_NET_GL620A USB_NET_MCS7830 USB_NET_NET1080 USB_NET_PLUSB USB_NET_RNDIS_HOST USB_NET_SMSC75XX USB_NET_SMSC95XX USB_NET_SR9700 USB_NET_SR9800 USB_NET_ZAURUS USB_OHCI_HCD USB_OHCI_HCD_PCI USB_OHCI_HCD_PLATFORM USB_OTG USB_OTG_FSM USB_PRINTER USB_SERIAL USB_SERIAL_FTDI_SIO USB_SERIAL_GENERIC USB_SERIAL_PL2303 USB_STORAGE_ALAUDA USB_STORAGE_CYPRESS_ATACB USB_STORAGE_DATAFAB USB_STORAGE_FREECOM USB_STORAGE_ISD200 USB_STORAGE_JUMPSHOT USB_STORAGE_KARMA USB_STORAGE_ONETOUCH USB_STORAGE_SDDR09 USB_STORAGE_SDDR55 USB_STORAGE_USBAT USB_TRANCEVIBRATOR USB_U_AUDIO USB_U_ETHER USB_U_SERIAL USB_WDM USB_XHCI_PCI_RENESAS WLAN WLAN_VENDOR_ATH WLAN_VENDOR_ATMEL WLAN_VENDOR_BROADCOM WLAN_VENDOR_INTERSIL WLAN_VENDOR_MARVELL WLAN_VENDOR_MEDIATEK WLAN_VENDOR_MICROCHIP WLAN_VENDOR_RALINK WLAN_VENDOR_REALTEK WLAN_VENDOR_RSI WLAN_VENDOR_ZYDAS X86_X32 ZEROPLUS_FF]
disabling configs for [HANG LEAK UBSAN BUG LOCKDEP ATOMIC_SLEEP], they are not needed
testing current HEAD 56993594bfa40da76f9c4f10bbb51634aa531edc
testing commit 56993594bfa40da76f9c4f10bbb51634aa531edc gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: 04093100fa11c6f99a5b8b04ead3fee3cdacc4430f1918f74eba3bdd43a5102b
run #0: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #1: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #2: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #3: crashed: KASAN: use-after-free Write in l2tp_session_delete
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
representative crash: KASAN: use-after-free Write in l2tp_session_delete, types: [KASAN]
crash still not fixed/happens on the oldest tested release
reproducer is flaky (0.60 repro chance estimate)
revisions tested: 7, total time: 1h40m7.000903497s (build: 17m42.298294211s, test: 1h20m10.777917527s)
crash still not fixed or there were kernel test errors
commit msg: Merge 5.15.183 into android13-5.15-lts
crash: KASAN: use-after-free Write in l2tp_session_delete
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:70 [inline]
BUG: KASAN: use-after-free in l2tp_session_delete+0x1e/0x440 net/l2tp/l2tp_core.c:1563
Write of size 8 at addr ffff88810a615808 by task kworker/u4:3/340

CPU: 1 PID: 340 Comm: kworker/u4:3 Not tainted 5.15.183-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: l2tp l2tp_tunnel_del_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x38/0x49 lib/dump_stack.c:106
 print_address_description.constprop.0+0x24/0x160 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report.cold+0x82/0xdb mm/kasan/report.c:444
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x148/0x190 mm/kasan/generic.c:189
 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:70 [inline]
 l2tp_session_delete+0x1e/0x440 net/l2tp/l2tp_core.c:1563
 l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1218 [inline]
 l2tp_tunnel_del_work+0x182/0x400 net/l2tp/l2tp_core.c:1258
 process_one_work+0x62c/0xec0 kernel/workqueue.c:2325
 worker_thread+0x48e/0xdb0 kernel/workqueue.c:2472
 kthread+0x324/0x3e0 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Allocated by task 9715:
 kasan_save_stack+0x26/0x50 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:433 [inline]
 ____kasan_kmalloc mm/kasan/common.c:512 [inline]
 ____kasan_kmalloc mm/kasan/common.c:471 [inline]
 __kasan_kmalloc+0xae/0xe0 mm/kasan/common.c:521
 kasan_kmalloc include/linux/kasan.h:227 [inline]
 __kmalloc+0x2e6/0x550 mm/slub.c:4431
 kmalloc include/linux/slab.h:621 [inline]
 kzalloc include/linux/slab.h:747 [inline]
 l2tp_session_create+0x38/0xa80 net/l2tp/l2tp_core.c:1599
 pppol2tp_connect+0xe03/0x1910 net/l2tp/l2tp_ppp.c:782
 __sys_connect_file+0x136/0x190 net/socket.c:1923
 __sys_connect+0x101/0x130 net/socket.c:1940
 __do_sys_connect net/socket.c:1950 [inline]
 __se_sys_connect net/socket.c:1947 [inline]
 __x64_sys_connect+0x6e/0xb0 net/socket.c:1947
 x64_sys_call+0x85c/0x990 arch/x86/include/generated/asm/syscalls_64.h:43
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x33/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 13:
 kasan_save_stack+0x26/0x50 mm/kasan/common.c:38
 kasan_set_track+0x25/0x30 mm/kasan/common.c:45
 kasan_set_free_info+0x24/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:365 [inline]
 ____kasan_slab_free mm/kasan/common.c:327 [inline]
 __kasan_slab_free+0x111/0x150 mm/kasan/common.c:373
 kasan_slab_free include/linux/kasan.h:193 [inline]
 slab_free_hook mm/slub.c:1723 [inline]
 slab_free_freelist_hook+0x94/0x1a0 mm/slub.c:1749
 slab_free mm/slub.c:3521 [inline]
 kfree+0xc2/0x2a0 mm/slub.c:4583
 l2tp_session_free net/l2tp/l2tp_core.c:168 [inline]
 l2tp_session_dec_refcount+0x7a/0x130 net/l2tp/l2tp_core.c:205
 pppol2tp_session_destruct+0xa3/0xd0 net/l2tp/l2tp_ppp.c:419
 __sk_destruct+0x42/0x520 net/core/sock.c:1962
 sk_destruct+0x9b/0xc0 net/core/sock.c:2007
 __sk_free+0xd1/0x350 net/core/sock.c:2018
 sk_free+0x45/0x60 net/core/sock.c:2029
 sock_put include/net/sock.h:1939 [inline]
 pppol2tp_put_sk+0x66/0x90 net/l2tp/l2tp_ppp.c:402
 rcu_do_batch+0x340/0xca0 kernel/rcu/tree.c:2523
 rcu_core+0x56b/0xac0 kernel/rcu/tree.c:2763
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2776
 handle_softirqs+0x1c5/0x510 kernel/softirq.c:565
 run_ksoftirqd kernel/softirq.c:941 [inline]
 run_ksoftirqd+0x2b/0x40 kernel/softirq.c:933
 smpboot_thread_fn+0x502/0x7b0 kernel/smpboot.c:164
 kthread+0x324/0x3e0 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Last potentially related work creation:
 kasan_save_stack+0x26/0x50 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xd8/0xf0 mm/kasan/generic.c:348
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
 __call_rcu_common.constprop.0+0xd7/0x11b0 kernel/rcu/tree.c:3007
 call_rcu+0x9/0x10 kernel/rcu/tree.c:3125
 pppol2tp_release+0x292/0x3e0 net/l2tp/l2tp_ppp.c:458
 __sock_release+0xc2/0x270 net/socket.c:649
 sock_close+0x10/0x20 net/socket.c:1336
 __fput+0x319/0x960 fs/file_table.c:311
 ____fput+0x9/0x10 fs/file_table.c:339
 task_work_run+0xc2/0x150 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:181 [inline]
 exit_to_user_mode_prepare+0x143/0x150 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x21/0x40 kernel/entry/common.c:307
 do_syscall_64+0x40/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88810a615800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
 512-byte region [ffff88810a615800, ffff88810a615a00)
The buggy address belongs to the page:
page:ffffea0004298500 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10a614
head:ffffea0004298500 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea00046e6700 0000000200000002 ffff888100042f00
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 474, ts 61187328456, free_ts 40768707215
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook mm/page_alloc.c:2605 [inline]
 prep_new_page+0x1a2/0x310 mm/page_alloc.c:2611
 get_page_from_freelist+0x1ce2/0x30a0 mm/page_alloc.c:4485
 __alloc_pages+0x2d5/0x2630 mm/page_alloc.c:5781
 __alloc_pages_node include/linux/gfp.h:591 [inline]
 alloc_pages_node include/linux/gfp.h:605 [inline]
 alloc_pages include/linux/gfp.h:618 [inline]
 alloc_slab_page mm/slub.c:1793 [inline]
 allocate_slab+0x39d/0x530 mm/slub.c:1932
 new_slab mm/slub.c:1995 [inline]
 ___slab_alloc.constprop.0+0x3ca/0x890 mm/slub.c:3028
 __slab_alloc.constprop.0+0x42/0x80 mm/slub.c:3115
 slab_alloc_node mm/slub.c:3206 [inline]
 slab_alloc mm/slub.c:3250 [inline]
 kmem_cache_alloc_trace+0x4a2/0x4e0 mm/slub.c:3267
 kmalloc include/linux/slab.h:616 [inline]
 kzalloc include/linux/slab.h:747 [inline]
 fib6_info_alloc+0x8d/0x180 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x2a6/0x18a0 net/ipv6/route.c:3784
 addrconf_f6i_alloc+0x237/0x400 net/ipv6/route.c:4584
 ipv6_add_addr+0x293/0x1cc0 net/ipv6/addrconf.c:1123
 inet6_addr_add+0x32d/0x8a0 net/ipv6/addrconf.c:3019
 inet6_rtm_newaddr+0x5e7/0x18c0 net/ipv6/addrconf.c:4977
 rtnetlink_rcv_msg+0x334/0x970 net/core/rtnetlink.c:5650
 netlink_rcv_skb+0x133/0x3c0 net/netlink/af_netlink.c:2493
 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:5668
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1472 [inline]
 free_pcp_prepare+0x1b6/0x4c0 mm/page_alloc.c:1544
 free_unref_page_prepare mm/page_alloc.c:3534 [inline]
 free_unref_page+0x84/0x760 mm/page_alloc.c:3616
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0xd7/0xf0 mm/page_alloc.c:5857
 __free_slab+0xdb/0x1c0 mm/slub.c:2020
 free_slab mm/slub.c:2035 [inline]
 discard_slab+0x2b/0x40 mm/slub.c:2041
 __unfreeze_partials+0x1e2/0x230 mm/slub.c:2527
 put_cpu_partial+0x96/0xb0 mm/slub.c:2607
 __slab_free+0x21e/0x4d0 mm/slub.c:3390
 do_slab_free mm/slub.c:3509 [inline]
 ___cache_free+0x1ee/0x230 mm/slub.c:3530
 qlink_free mm/kasan/quarantine.c:157 [inline]
 qlist_free_all+0x6e/0x150 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x15f/0x1c0 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0xaa/0xc0 mm/kasan/common.c:443
 kasan_slab_alloc include/linux/kasan.h:217 [inline]
 slab_post_alloc_hook mm/slab.h:550 [inline]
 slab_alloc_node mm/slub.c:3240 [inline]
 slab_alloc mm/slub.c:3250 [inline]
 kmem_cache_alloc+0x179/0x4d0 mm/slub.c:3255
 getname_flags.part.0+0x4d/0x480 fs/namei.c:138
 getname_flags+0x7d/0xd0 include/linux/audit.h:319
 user_path_at_empty+0x23/0x60 fs/namei.c:2882

Memory state around the buggy address:
 ffff88810a615700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810a615780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88810a615800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88810a615880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88810a615900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================