bisecting fixing commit since 811218eceeaa7618652e1b8d11caeff67ab42072 building syzkaller on a5f86b15f4f60350198e4b98fb7451d45d38a186 testing commit 811218eceeaa7618652e1b8d11caeff67ab42072 with gcc (GCC) 8.4.1 20210217 kernel signature: 61b43660dfc7b73b7e1f9a8b9861656eb8e199950d1fb20b69907fa48eb11553 run #0: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #1: crashed: KASAN: use-after-free Write in ext4_write_inline_data run #2: crashed: KASAN: use-after-free Write in ext4_write_inline_data run #3: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #4: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #5: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #6: crashed: KASAN: use-after-free Write in ext4_write_inline_data run #7: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #8: crashed: KASAN: use-after-free Write in ext4_write_inline_data run #9: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #10: crashed: KASAN: use-after-free Write in ext4_write_inline_data run #11: crashed: KASAN: use-after-free Write in ext4_write_inline_data run #12: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #13: crashed: KASAN: use-after-free Write in ext4_write_inline_data run #14: crashed: KASAN: use-after-free Write in ext4_write_inline_data run #15: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #16: crashed: KASAN: use-after-free Write in ext4_write_inline_data run #17: crashed: KASAN: use-after-free Write in ext4_write_inline_data run #18: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #19: crashed: KASAN: use-after-free Write in ext4_write_inline_data testing current HEAD 9f84340f012ee60c12aacc03662bcdd67419a31a testing commit 9f84340f012ee60c12aacc03662bcdd67419a31a with gcc (GCC) 8.4.1 20210217 kernel signature: 5cabb04844832179046aa327779dfa5cce92a0671e4cb3c56425d9a0721ca38d run #0: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #1: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #2: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #3: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #4: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #5: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #6: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #7: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #8: crashed: KASAN: slab-out-of-bounds Write in ext4_write_inline_data run #9: crashed: KASAN: use-after-free Write in ext4_write_inline_data revisions tested: 2, total time: 22m44.81843531s (build: 15m33.219447566s, test: 6m42.230727604s) the crash still happens on HEAD commit msg: Linux 4.19.196 crash: KASAN: use-after-free Write in ext4_write_inline_data batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 ================================================================== batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! BUG: KASAN: use-after-free in memcpy include/linux/string.h:377 [inline] BUG: KASAN: use-after-free in ext4_write_inline_data.isra.4+0x27a/0x480 fs/ext4/inline.c:245 Write of size 70 at addr ffff8880a00ef4ef by task syz-executor.5/9843 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 CPU: 1 PID: 9843 Comm: syz-executor.5 Not tainted 4.19.196-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x17c/0x226 lib/dump_stack.c:118 print_address_description.cold.6+0x9/0x211 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:396 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13c/0x1b0 mm/kasan/kasan.c:267 memcpy+0x37/0x50 mm/kasan/kasan.c:303 memcpy include/linux/string.h:377 [inline] ext4_write_inline_data.isra.4+0x27a/0x480 fs/ext4/inline.c:245 ext4_write_inline_data_end+0x1df/0x530 fs/ext4/inline.c:754 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 ext4_write_end+0x167/0xb10 fs/ext4/inode.c:1423 ext4_da_write_end+0x622/0x9b0 fs/ext4/inode.c:3170 generic_perform_write+0x2e3/0x480 mm/filemap.c:3181 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! __generic_file_write_iter+0x205/0x590 mm/filemap.c:3295 ext4_file_write_iter+0x281/0xe50 fs/ext4/file.c:272 IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready call_write_iter include/linux/fs.h:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x443/0x890 fs/read_write.c:487 vfs_write+0x150/0x4d0 fs/read_write.c:549 ksys_write+0x103/0x260 fs/read_write.c:599 __do_sys_write fs/read_write.c:611 [inline] __se_sys_write fs/read_write.c:608 [inline] __x64_sys_write+0x6e/0xb0 fs/read_write.c:608 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3c0c635188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465b09 RDX: 0000000000000082 RSI: 0000000020000180 RDI: 0000000000000003 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 batman_adv: batadv0: Interface activated: batadv_slave_1 R13: 00007fff06120baf R14: 00007f3c0c635300 R15: 0000000000022000 Allocated by task 8484: save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:553 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:538 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x50/0x70 mm/slab.c:3703 __kmalloc_reserve.isra.9+0x2c/0xc0 net/core/skbuff.c:137 pskb_expand_head+0x113/0xd80 net/core/skbuff.c:1473 netlink_trim+0x1a7/0x200 net/netlink/af_netlink.c:1302 netlink_broadcast_filtered+0x57/0x900 net/netlink/af_netlink.c:1499 netlink_broadcast+0xe/0x10 net/netlink/af_netlink.c:1544 nlmsg_multicast include/net/netlink.h:591 [inline] nlmsg_notify+0x107/0x140 net/netlink/af_netlink.c:2500 rtnl_notify net/core/rtnetlink.c:736 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:3377 [inline] rtmsg_ifinfo_event.part.14+0x7f/0xb0 net/core/rtnetlink.c:3392 rtmsg_ifinfo_event net/core/rtnetlink.c:3400 [inline] rtmsg_ifinfo+0x4e/0x70 net/core/rtnetlink.c:3398 __dev_notify_flags+0x1a1/0x240 net/core/dev.c:7705 ieee80211 phy6: Selected rate control algorithm 'minstrel_ht' dev_change_flags+0xe6/0x150 net/core/dev.c:7745 do_setlink+0x11c1/0x2ec0 net/core/rtnetlink.c:2449 rtnl_newlink+0x975/0x1360 net/core/rtnetlink.c:3077 rtnetlink_rcv_msg+0x34f/0x950 net/core/rtnetlink.c:4782 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2457 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4800 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x443/0x660 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x667/0xc60 net/netlink/af_netlink.c:1911 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:661 __sys_sendto+0x1f2/0x2e0 net/socket.c:1897 __do_sys_sendto net/socket.c:1909 [inline] __se_sys_sendto net/socket.c:1905 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1905 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8484: save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x13c/0x220 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 skb_free_head+0x74/0x90 net/core/skbuff.c:563 skb_release_data+0x513/0x760 net/core/skbuff.c:583 skb_release_all+0x3d/0x50 net/core/skbuff.c:640 __kfree_skb net/core/skbuff.c:654 [inline] consume_skb+0x93/0x270 net/core/skbuff.c:714 netlink_broadcast_filtered+0x28e/0x900 net/netlink/af_netlink.c:1522 netlink_broadcast+0xe/0x10 net/netlink/af_netlink.c:1544 nlmsg_multicast include/net/netlink.h:591 [inline] nlmsg_notify+0x107/0x140 net/netlink/af_netlink.c:2500 rtnl_notify net/core/rtnetlink.c:736 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:3377 [inline] rtmsg_ifinfo_event.part.14+0x7f/0xb0 net/core/rtnetlink.c:3392 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 rtmsg_ifinfo_event net/core/rtnetlink.c:3400 [inline] rtmsg_ifinfo+0x4e/0x70 net/core/rtnetlink.c:3398 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! __dev_notify_flags+0x1a1/0x240 net/core/dev.c:7705 dev_change_flags+0xe6/0x150 net/core/dev.c:7745 do_setlink+0x11c1/0x2ec0 net/core/rtnetlink.c:2449 rtnl_newlink+0x975/0x1360 net/core/rtnetlink.c:3077 rtnetlink_rcv_msg+0x34f/0x950 net/core/rtnetlink.c:4782 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2457 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4800 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x443/0x660 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x667/0xc60 net/netlink/af_netlink.c:1911 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:661 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! __sys_sendto+0x1f2/0x2e0 net/socket.c:1897 __do_sys_sendto net/socket.c:1909 [inline] __se_sys_sendto net/socket.c:1905 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1905 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a00ef180 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 879 bytes inside of 2048-byte region [ffff8880a00ef180, ffff8880a00ef980) The buggy address belongs to the page: page:ffffea0002803b80 count:1 mapcount:0 mapping:ffff88813bff6c40 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea00027b3388 ffffea0002788808 ffff88813bff6c40 raw: 0000000000000000 ffff8880a00ee080 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a00ef380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a00ef400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a00ef480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a00ef500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a00ef580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1