------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#0: syz.1.1370/10362 Modules linked in: CPU: 0 UID: 0 PID: 10362 Comm: syz.1.1370 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25 Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 6b 66 26 fd 48 8d 3d 94 5f d6 0a 67 48 0f b9 3a eb 4a e8 58 66 26 fd 48 8d 3d 91 5f d6 0a <67> 48 0f b9 3a eb 37 e8 45 66 26 fd 48 8d 3d 8e 5f d6 0a 67 48 0f RSP: 0018:ffffc9000e7376d8 EFLAGS: 00010287 RAX: ffffffff849e10a8 RBX: 0000000000000002 RCX: 0000000000080000 RDX: ffffc9000f54a000 RSI: 0000000000000783 RDI: ffffffff8f747040 RBP: 0000000000000000 R08: ffff88805f9b9e80 R09: 0000000000000005 R10: 0000000000000100 R11: 0000000000000004 R12: ffffffff8c049388 R13: dffffc0000000000 R14: ffff88803728cd98 R15: dffffc0000000000 FS: 00007f36ee9156c0(0000) GS:ffff88812633c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f36ee8f3ff8 CR3: 00000000261a2000 CR4: 00000000003526f0 Call Trace: __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] kref_get include/linux/kref.h:45 [inline] kobject_get+0xfa/0x120 lib/kobject.c:643 i2c_get_adapter+0x6d/0xa0 drivers/i2c/i2c-core-base.c:2612 i2cdev_open+0x48/0x190 drivers/i2c/i2c-dev.c:603 chrdev_open+0x4d0/0x5f0 fs/char_dev.c:411 do_dentry_open+0x83d/0x13e0 fs/open.c:949 vfs_open+0x3b/0x350 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x2e43/0x38a0 fs/namei.c:4830 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f36f069cfce Code: 08 0f 85 a5 a8 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 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007f36ee914b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f36ee9156c0 RCX: 00007f36f069cfce RDX: 0000000000000402 RSI: 00007f36ee914c00 RDI: ffffffffffffff9c RBP: 00007f36ee914c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007f36f0956128 R14: 00007f36f0956090 R15: 00007ffc4a00bd38 ---------------- Code disassembly (best guess): 0: eb 66 jmp 0x68 2: 85 db test %ebx,%ebx 4: 74 3e je 0x44 6: 83 fb 01 cmp $0x1,%ebx 9: 75 4c jne 0x57 b: e8 6b 66 26 fd call 0xfd26667b 10: 48 8d 3d 94 5f d6 0a lea 0xad65f94(%rip),%rdi # 0xad65fab 17: 67 48 0f b9 3a ud1 (%edx),%rdi 1c: eb 4a jmp 0x68 1e: e8 58 66 26 fd call 0xfd26667b 23: 48 8d 3d 91 5f d6 0a lea 0xad65f91(%rip),%rdi # 0xad65fbb * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: eb 37 jmp 0x68 31: e8 45 66 26 fd call 0xfd26667b 36: 48 8d 3d 8e 5f d6 0a lea 0xad65f8e(%rip),%rdi # 0xad65fcb 3d: 67 addr32 3e: 48 rex.W 3f: 0f .byte 0xf