bisecting cause commit starting from f8456690ba8eb18ea4714e68554e242a04f65cff building syzkaller on 54b3c45e2881a2cc71d06d21f0ca39b6e47666db testing commit f8456690ba8eb18ea4714e68554e242a04f65cff with gcc (GCC) 8.1.0 kernel signature: b083daa9aebcd10a128802fd5bed88cded5ecc8a6afc59d017ce37bff84d913c all runs: crashed: WARNING in snd_info_get_line testing release v5.7 testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.1.0 kernel signature: 9358d33ed02048202c86cd717a612f510e16f54fdbcef81b6b14edcb03221299 all runs: crashed: WARNING in snd_info_get_line testing release v5.6 testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0 kernel signature: 07f2f693d1f7e9051193d24be0e0e54d6272714e0c73e3e0146548d53b1a9895 all runs: crashed: WARNING in snd_info_get_line testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: a7718c37490c6951f92bdec38e93a7a9b1e8e7673d00929c3b7dc0e9628ff307 all runs: crashed: WARNING in snd_info_get_line testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: 607e4f55fe4c91ba1d2c93e0d1fb534806c816adf77c84c4cf42c32078a63c7a all runs: crashed: WARNING in snd_info_get_line testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: 319b634a44a2d22e2fd32a79ce11cffc184ed33d183629d6c5422febeb90ac81 all runs: crashed: WARNING in snd_info_get_line testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: 4be2022d32d1c3dab917417492482ecff6bd8361b678bee29b57c6fe6268a22a all runs: crashed: WARNING in snd_info_get_line testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: ac9d217226a243785a23494806cdcdf2a8a1cb3d7219391727a0ef1d92b1dc39 all runs: crashed: WARNING in snd_info_get_line testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: 94c30d91933e4ab869708039032706becd1c79ec4b4151179cd527a691e02856 run #0: crashed: WARNING in snd_info_get_line run #1: crashed: WARNING in corrupted run #2: crashed: WARNING in snd_info_get_line run #3: crashed: WARNING in corrupted run #4: crashed: WARNING in snd_info_get_line run #5: crashed: WARNING in snd_info_get_line run #6: crashed: WARNING in corrupted run #7: crashed: WARNING in corrupted run #8: crashed: WARNING in snd_info_get_line run #9: crashed: WARNING in corrupted testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: 4bd914e21c0dd9fa4965d243e4ce8cecd6233825b691aab7b9b7908baf9e1a0f run #0: crashed: WARNING in snd_info_get_line run #1: crashed: WARNING in corrupted run #2: crashed: WARNING in corrupted run #3: crashed: WARNING in snd_info_get_line run #4: crashed: WARNING in snd_info_get_line run #5: crashed: WARNING in snd_info_get_line run #6: crashed: WARNING in snd_info_get_line run #7: crashed: WARNING in snd_info_get_line run #8: crashed: WARNING in snd_info_get_line run #9: crashed: WARNING in snd_info_get_line testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: bd8bc1eb4346c823df7bcb7c2fd119da942c6c451c7a5cc250950c08edf2c1d9 run #0: crashed: WARNING in corrupted run #1: crashed: WARNING in snd_info_get_line run #2: crashed: WARNING in snd_info_get_line run #3: crashed: WARNING in snd_info_get_line run #4: crashed: WARNING in snd_info_get_line run #5: crashed: WARNING in snd_info_get_line run #6: crashed: WARNING in snd_info_get_line run #7: crashed: WARNING in corrupted run #8: crashed: WARNING in snd_info_get_line run #9: crashed: WARNING in snd_info_get_line testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: 56d7fce1193181ee8718bf66d8a520a0f787d9e74a909e2c1e881a6d08f564c3 run #0: crashed: WARNING in snd_info_get_line run #1: crashed: WARNING in corrupted run #2: crashed: WARNING in snd_info_get_line run #3: crashed: WARNING in snd_info_get_line run #4: crashed: WARNING in snd_info_get_line run #5: crashed: WARNING in snd_info_get_line run #6: crashed: WARNING in snd_info_get_line run #7: crashed: WARNING in snd_info_get_line run #8: crashed: WARNING in snd_info_get_line run #9: crashed: WARNING in corrupted testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 3801b7682f9788730cd7e5f232e4e9f4f67e81a197e20ebe9a19884bee08ff7d run #0: crashed: WARNING in snd_info_get_line run #1: crashed: WARNING in snd_info_get_line run #2: crashed: WARNING in snd_info_get_line run #3: crashed: WARNING in snd_info_get_line run #4: crashed: WARNING in snd_info_get_line run #5: crashed: WARNING in corrupted run #6: crashed: WARNING in snd_info_get_line run #7: crashed: WARNING in snd_info_get_line run #8: crashed: WARNING in snd_info_get_line run #9: crashed: WARNING in corrupted testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: 63723637fbe9d87ecccc0e2c2376d9212eed76aca0a01e9681231efe66d577f7 run #0: crashed: WARNING in snd_info_get_line run #1: crashed: WARNING in snd_info_get_line run #2: crashed: WARNING in snd_info_get_line run #3: crashed: WARNING in snd_info_get_line run #4: crashed: WARNING in snd_info_get_line run #5: crashed: WARNING in snd_info_get_line run #6: crashed: WARNING in corrupted run #7: crashed: WARNING in snd_info_get_line run #8: crashed: WARNING in snd_info_get_line run #9: crashed: WARNING in corrupted testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: a31a236dab723b8b3786e8560b9db1f8340596b43a6874ee6b91e6d0b28deb2d all runs: crashed: WARNING in snd_info_get_line testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: 25df35179ec4c5b682feef9c0f80bd543062a810dc064943455f7fce2eae61ea all runs: crashed: WARNING in snd_info_get_line testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 74d5b47e6e39988341f31f5727ebfa888bad68cf2d71469710439967e681296f run #0: crashed: WARNING in corrupted run #1: crashed: WARNING in corrupted run #2: crashed: WARNING in snd_info_get_line run #3: crashed: WARNING in corrupted run #4: crashed: WARNING in corrupted run #5: crashed: WARNING in snd_info_get_line run #6: crashed: WARNING in corrupted run #7: crashed: WARNING in snd_info_get_line run #8: crashed: WARNING in snd_info_get_line run #9: crashed: WARNING in snd_info_get_line testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 363c6707236066512fa460575032d2bd9234ad9daa8e76b2ef92dd4be5728838 all runs: crashed: BUG: sleeping function called from invalid context in tap_get_minor testing release v4.11 testing commit a351e9b9fc24e982ec2f0e76379a49826036da12 with gcc (GCC) 7.3.0 kernel signature: a0f6aa2462b92308dd3d4d1eb73bcfe245b46d23da299596869b7cf41fa6f7d9 all runs: crashed: BUG: sleeping function called from invalid context in tap_get_minor testing release v4.10 testing commit c470abd4fde40ea6a0846a2beab642a578c0b8cd with gcc (GCC) 5.5.0 kernel signature: 0867f7eb7018bb996532f49e87e89612627f0fe7e308ededfd6fe632f390b6bc run #0: crashed: WARNING in snd_info_get_line run #1: crashed: WARNING in snd_info_get_line run #2: crashed: WARNING in snd_info_get_line run #3: crashed: WARNING in snd_info_get_line run #4: crashed: WARNING in corrupted run #5: crashed: WARNING in snd_info_get_line run #6: crashed: WARNING in snd_info_get_line run #7: crashed: WARNING in snd_info_get_line run #8: crashed: WARNING in snd_info_get_line run #9: crashed: WARNING in snd_info_get_line testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: 50a9785c48747c46bcdc8bc5cce531035ea91c4ddf921ca75f87282544d92b16 all runs: crashed: WARNING in snd_info_get_line testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: 08a948f9455f3a4f96d3132aab62620aaba19a4dfcba124fd94306a2092f8e67 all runs: basic kernel testing failed: timed out testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: b7ac06497c6b1e76ee1e45c23bd115dbd99413b5c0be194aca6b5136efc08f77 all runs: crashed: WARNING in snd_info_get_line testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: 1de3860504e09f977d745557c3e3fbec59546aa38a0d59baac06b21816bf1d3a all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 24, total time: 3h39m42.66803121s (build: 2h18m3.028036438s, test: 1h17m28.727378576s) the crash already happened on the oldest tested release commit msg: Linux 4.6 crash: WARNING in sysfs_warn_dup IPv6: ADDRCONF(NETDEV_UP): hsr_slave_0: link is not ready IPv6: ADDRCONF(NETDEV_UP): hsr_slave_1: link is not ready bond0: Enslaving bond_slave_0 as an active interface with an up link bond0: Enslaving bond_slave_1 as an active interface with an up link ------------[ cut here ]------------ WARNING: CPU: 1 PID: 5877 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x7b/0xa0 fs/sysfs/dir.c:30 sysfs: cannot create duplicate filename '/class/macvtap/tap50' Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 5877 Comm: syz-executor.4 Not tainted 4.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 ffff88012889efc8 ffffffff82c65e52 ffffffff85c81040 ffff88012889f0a0 ffffffff85d2bb80 ffffffff8191bd7b 0000000000000009 ffff88012889f090 ffffffff8160d884 0000000041b58ab3 ffffffff868f3402 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0x136/0x1d4 lib/dump_stack.c:51 [] panic+0x1af/0x348 kernel/panic.c:152 [] __warn+0x18d/0x1b0 kernel/panic.c:504 [] warn_slowpath_fmt+0x92/0xb0 kernel/panic.c:527 [] sysfs_warn_dup+0x7b/0xa0 fs/sysfs/dir.c:30 [] sysfs_do_create_link_sd.isra.0+0xd1/0xf0 fs/sysfs/symlink.c:51 [] sysfs_do_create_link fs/sysfs/symlink.c:80 [inline] [] sysfs_create_link+0x43/0xb0 fs/sysfs/symlink.c:92 [] device_add_class_symlinks drivers/base/core.c:891 [inline] [] device_add+0x677/0x1350 drivers/base/core.c:1086 [] device_create_groups_vargs+0x1c8/0x220 drivers/base/core.c:1709 [] device_create_vargs drivers/base/core.c:1749 [inline] [] device_create+0x88/0xa0 drivers/base/core.c:1785 [] macvtap_device_event+0x1c4/0x2a0 drivers/net/macvtap.c:1298 [] notifier_call_chain+0x8b/0x170 kernel/notifier.c:93 [] __raw_notifier_call_chain kernel/notifier.c:394 [inline] [] raw_notifier_call_chain+0x11/0x20 kernel/notifier.c:401 [] call_netdevice_notifiers_info+0x47/0x80 net/core/dev.c:1643 [] call_netdevice_notifiers net/core/dev.c:1659 [inline] [] register_netdevice+0x8e8/0xd00 net/core/dev.c:7027 [] macvlan_common_newlink+0x8b9/0x1090 drivers/net/macvlan.c:1316 [] macvtap_newlink+0xbf/0x110 drivers/net/macvtap.c:471 [] rtnl_newlink+0xd4b/0x1230 net/core/rtnetlink.c:2466 [] rtnetlink_rcv_msg+0x222/0x680 net/core/rtnetlink.c:3513 [] netlink_rcv_skb+0x242/0x350 net/netlink/af_netlink.c:2277 [] rtnetlink_rcv+0x25/0x30 net/core/rtnetlink.c:3519 [] netlink_unicast_kernel net/netlink/af_netlink.c:1214 [inline] [] netlink_unicast+0x3da/0x560 net/netlink/af_netlink.c:1240 [] netlink_sendmsg+0x9bb/0xb40 net/netlink/af_netlink.c:1786 [] sock_sendmsg_nosec net/socket.c:612 [inline] [] sock_sendmsg+0xb5/0xf0 net/socket.c:622 [] SYSC_sendto net/socket.c:1648 [inline] [] SyS_sendto+0x1ca/0x290 net/socket.c:1616 [] entry_SYSCALL_64_fastpath+0x23/0xc1 Kernel Offset: disabled