bisecting fixing commit since 0bf999f9c5e74c7ecf9dafb527146601e5c848b9
building syzkaller on c5ed587f4af5e639f7373d8ebf10ac049cb9c71b
testing commit 0bf999f9c5e74c7ecf9dafb527146601e5c848b9 with gcc (GCC) 8.1.0
kernel signature: cf857050ab96e2aa4a8ce138aa753cd6cd16f5ddc2e314c1aa582d895a0d63b5
all runs: crashed: BUG: unable to handle kernel paging request in do_xdp_generic
testing current HEAD 5d286d5ebcf6cb93b340f2439fe16a90b544c6e5
testing commit 5d286d5ebcf6cb93b340f2439fe16a90b544c6e5 with gcc (GCC) 8.1.0
kernel signature: 42a9ae645ee04eb79ba4669753d645b11f55c332a4adfd4165e661c6bffc4dbf
all runs: crashed: BUG: unable to handle kernel paging request in do_xdp_generic
revisions tested: 2, total time: 19m24.880550553s (build: 12m7.205813893s, test: 6m47.392423362s)
the crash still happens on HEAD
commit msg: Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
crash: BUG: unable to handle kernel paging request in do_xdp_generic
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready
BUG: unable to handle page fault for address: ffff887f9ccddfff
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 8516 Comm: syz-executor.2 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:is_multicast_ether_addr_64bits include/linux/etherdevice.h:135 [inline]
RIP: 0010:netif_receive_generic_xdp net/core/dev.c:4555 [inline]
RIP: 0010:do_xdp_generic.part.132+0x3dd/0x17f0 net/core/dev.c:4652
Code: 4d 89 74 24 b0 49 89 44 24 a8 48 89 85 18 ff ff ff 48 b8 00 00 00 00 00 fc ff df 4d 89 7c 24 b8 80 3c 02 00 0f 85 bd 0f 00 00 <49> 8b 06 49 8d 7e 0c 48 ba 00 00 00 00 00 fc ff df 48 89 85 00 ff
RSP: 0018:ffffc90004c976e8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 1ffff92000992eed RCX: ffffffff0000feff
RDX: 1ffff10ff399bbff RSI: 0000000000000000 RDI: ffffffffffff0101
RBP: ffffc90004c97810 R08: ffff8880a77cf176 R09: ffffed1013999c5d
R10: ffff88809ccce2e3 R11: ffffed1013999c5c R12: ffffc90004c977e8
R13: ffff8880a77cf0c0 R14: ffff887f9ccddfff R15: ffff88809ccce000
FS:  00007f8438b29700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff887f9ccddfff CR3: 0000000095da2000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_xdp_generic+0xe/0x20 net/core/dev.c:4646
 tun_get_user+0x2197/0x3840 drivers/net/tun.c:1901
 tun_chr_write_iter+0xb5/0x156 drivers/net/tun.c:1992
 call_write_iter include/linux/fs.h:1907 [inline]
 do_iter_readv_writev+0x532/0xa70 fs/read_write.c:694
 do_iter_write+0x130/0x510 fs/read_write.c:999
 vfs_writev+0x16d/0x2d0 fs/read_write.c:1072
 do_writev+0x118/0x2e0 fs/read_write.c:1115
 __do_sys_writev fs/read_write.c:1188 [inline]
 __se_sys_writev fs/read_write.c:1185 [inline]
 __x64_sys_writev+0x70/0xb0 fs/read_write.c:1185
 do_syscall_64+0xca/0x630 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c581
Code: 75 14 b8 14 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 e4 b7 fb ff c3 48 83 ec 08 e8 fa 2c 00 00 48 89 04 24 b8 14 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 43 2d 00 00 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007f8438b28ba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 0000000000000066 RCX: 000000000045c581
RDX: 0000000000000001 RSI: 00007f8438b28c00 RDI: 00000000000000f0
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00000000ffffffff
R13: 0000000000000b7c R14: 00000000004cd906 R15: 000000000076bf2c
Modules linked in:
CR2: ffff887f9ccddfff
---[ end trace 19fd8c7bb3f0f11c ]---
RIP: 0010:is_multicast_ether_addr_64bits include/linux/etherdevice.h:135 [inline]
RIP: 0010:netif_receive_generic_xdp net/core/dev.c:4555 [inline]
RIP: 0010:do_xdp_generic.part.132+0x3dd/0x17f0 net/core/dev.c:4652
Code: 4d 89 74 24 b0 49 89 44 24 a8 48 89 85 18 ff ff ff 48 b8 00 00 00 00 00 fc ff df 4d 89 7c 24 b8 80 3c 02 00 0f 85 bd 0f 00 00 <49> 8b 06 49 8d 7e 0c 48 ba 00 00 00 00 00 fc ff df 48 89 85 00 ff
RSP: 0018:ffffc90004c976e8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 1ffff92000992eed RCX: ffffffff0000feff
RDX: 1ffff10ff399bbff RSI: 0000000000000000 RDI: ffffffffffff0101
RBP: ffffc90004c97810 R08: ffff8880a77cf176 R09: ffffed1013999c5d
R10: ffff88809ccce2e3 R11: ffffed1013999c5c R12: ffffc90004c977e8
R13: ffff8880a77cf0c0 R14: ffff887f9ccddfff R15: ffff88809ccce000
FS:  00007f8438b29700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff887f9ccddfff CR3: 0000000095da2000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400