------------[ cut here ]------------ WARNING: CPU: 0 PID: 13896 at lib/refcount.c:25 refcount_warn_saturate+0x108/0x174 lib/refcount.c:25 refcount_t: addition on 0; use-after-free. Modules linked in: Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 13896 Comm: syz-executor.1 Not tainted 5.12.0-rc3-syzkaller #0 Hardware name: ARM-Versatile Express Backtrace: [<81802550>] (dump_backtrace) from [<818027c4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:252) r7:00000080 r6:60000093 r5:00000000 r4:82b58344 [<818027ac>] (show_stack) from [<81809e98>] (__dump_stack lib/dump_stack.c:79 [inline]) [<818027ac>] (show_stack) from [<81809e98>] (dump_stack+0xb8/0xe8 lib/dump_stack.c:120) [<81809de0>] (dump_stack) from [<81803358>] (panic+0x130/0x378 kernel/panic.c:231) r7:81f48198 r6:82a390a4 r5:00000000 r4:82c6b0d0 [<81803228>] (panic) from [<802446f4>] (__warn+0xb0/0x164 kernel/panic.c:605) r3:82a2248c r2:00000000 r1:00000000 r0:81f48198 r7:00000019 [<80244644>] (__warn) from [<8180363c>] (warn_slowpath_fmt+0x9c/0xd4 kernel/panic.c:635) r7:807f727c r6:00000019 r5:81fa03ec r4:81fa03fc [<818035a4>] (warn_slowpath_fmt) from [<807f727c>] (refcount_warn_saturate+0x108/0x174 lib/refcount.c:25) r8:8653c000 r7:0000011a r6:8653c000 r5:860f1380 r4:866dc000 [<807f7174>] (refcount_warn_saturate) from [<816d2270>] (__refcount_add include/linux/refcount.h:199 [inline]) [<807f7174>] (refcount_warn_saturate) from [<816d2270>] (__refcount_inc include/linux/refcount.h:250 [inline]) [<807f7174>] (refcount_warn_saturate) from [<816d2270>] (refcount_inc include/linux/refcount.h:267 [inline]) [<807f7174>] (refcount_warn_saturate) from [<816d2270>] (kref_get include/linux/kref.h:45 [inline]) [<807f7174>] (refcount_warn_saturate) from [<816d2270>] (j1939_netdev_start+0x280/0x388 net/can/j1939/main.c:250) [<816d1ff0>] (j1939_netdev_start) from [<816d3c7c>] (j1939_sk_bind+0xf0/0x304 net/can/j1939/socket.c:479) r8:8653c000 r7:0000011a r6:86974800 r5:860f1380 r4:8351bef4 [<816d3b8c>] (j1939_sk_bind) from [<81324080>] (__sys_bind+0xc8/0xd8 net/socket.c:1637) r10:0000011a r9:8351a000 r8:80200224 r7:0000011a r6:00000018 r5:860f1380 r4:20000000 [<81323fb8>] (__sys_bind) from [<813240a0>] (__do_sys_bind net/socket.c:1648 [inline]) [<81323fb8>] (__sys_bind) from [<813240a0>] (sys_bind+0x10/0x14 net/socket.c:1646) r6:00000000 r5:00000000 r4:00000000 [<81324090>] (sys_bind) from [<80200060>] (ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64) Exception stack(0x8351bfa8 to 0x8351bff0) bfa0: 00000000 00000000 00000008 20000000 00000018 00000000 bfc0: 00000000 00000000 00000000 0000011a 7ee6e332 76f7f6d0 7ee6e4ac 76f7f20c bfe0: 76f7f048 76f7f038 00018bf8 0004b480 Rebooting in 86400 seconds..