Re: KMSAN: uninit-value in __skb_flow_dissect (3)
On Wed, Jul 22, 2020 at 11:53 AM syzbot wrote: > > Hello, > > syzbot found the following issue on: Sorry for the noise. This is a false report caused by incorrect copy_to_user() instrumentation after KMSAN rebase. Should be fixed now. #syz invalid > HEAD commit:14525656 compiler.h: reinstate missing KMSAN_INIT > git tree: https://github.com/google/kmsan.git master > console output: https://syzkaller.appspot.com/x/log.txt?x=154bb20f10 > kernel config: https://syzkaller.appspot.com/x/.config?x=c534a9fad6323722 > dashboard link: https://syzkaller.appspot.com/bug?extid=051a531e8f1f59cf6dc9 > compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ > c2443155a0fb245c8f17f2c1c72b6ea391e86e81) > userspace arch: i386 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1394665890 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17adcb6f10 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+051a531e8f1f59cf6...@syzkaller.appspotmail.com > > batman_adv: batadv0: Interface activated: batadv_slave_1 > = > BUG: KMSAN: uninit-value in __skb_flow_dissect+0x30f0/0x8440 > net/core/flow_dissector.c:1163 > CPU: 0 PID: 8524 Comm: syz-executor152 Not tainted 5.8.0-rc5-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+0x1df/0x240 lib/dump_stack.c:118 > kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 > __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 > __skb_flow_dissect+0x30f0/0x8440 net/core/flow_dissector.c:1163 > skb_flow_dissect_flow_keys include/linux/skbuff.h:1310 [inline] > ___skb_get_hash net/core/flow_dissector.c:1520 [inline] > __skb_get_hash+0x131/0x480 net/core/flow_dissector.c:1586 > skb_get_hash include/linux/skbuff.h:1348 [inline] > udp_flow_src_port+0xa5/0x690 include/net/udp.h:220 > geneve_xmit_skb drivers/net/geneve.c:895 [inline] > geneve_xmit+0xdf1/0x2bf0 drivers/net/geneve.c:1005 > __netdev_start_xmit include/linux/netdevice.h:4611 [inline] > netdev_start_xmit include/linux/netdevice.h:4625 [inline] > xmit_one net/core/dev.c:3556 [inline] > dev_hard_start_xmit+0x50e/0xa70 net/core/dev.c:3572 > __dev_queue_xmit+0x2f8d/0x3b20 net/core/dev.c:4131 > dev_queue_xmit+0x4b/0x60 net/core/dev.c:4164 > pppoe_sendmsg+0xb43/0xb90 drivers/net/ppp/pppoe.c:900 > sock_sendmsg_nosec net/socket.c:652 [inline] > sock_sendmsg net/socket.c:672 [inline] > kernel_sendmsg+0x433/0x440 net/socket.c:692 > sock_no_sendpage+0x235/0x300 net/core/sock.c:2853 > kernel_sendpage net/socket.c:3644 [inline] > sock_sendpage+0x25b/0x2c0 net/socket.c:945 > pipe_to_sendpage+0x38c/0x4c0 fs/splice.c:448 > splice_from_pipe_feed fs/splice.c:502 [inline] > __splice_from_pipe+0x565/0xf00 fs/splice.c:626 > splice_from_pipe fs/splice.c:661 [inline] > generic_splice_sendpage+0x1d5/0x2d0 fs/splice.c:834 > do_splice_from fs/splice.c:846 [inline] > direct_splice_actor+0x1fd/0x580 fs/splice.c:1016 > splice_direct_to_actor+0x6b2/0xf50 fs/splice.c:971 > do_splice_direct+0x342/0x580 fs/splice.c:1059 > do_sendfile+0x101b/0x1d40 fs/read_write.c:1540 > __do_compat_sys_sendfile fs/read_write.c:1622 [inline] > __se_compat_sys_sendfile+0x301/0x3c0 fs/read_write.c:1605 > __ia32_compat_sys_sendfile+0x56/0x70 fs/read_write.c:1605 > do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline] > __do_fast_syscall_32+0x2aa/0x400 arch/x86/entry/common.c:477 > do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505 > do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554 > entry_SYSENTER_compat_after_hwframe+0x4d/0x5c > RIP: 0023:0xf7f13549 > Code: Bad RIP value. > RSP: 002b:ffd520cc EFLAGS: 0217 ORIG_RAX: 00bb > RAX: ffda RBX: 0006 RCX: 0005 > RDX: RSI: 7fff RDI: 0006 > RBP: 2000 R08: R09: > R10: R11: R12: > R13: R14: R15: > > Uninit was stored to memory at: > kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] > kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310 > kmsan_memcpy_memmove_metadata+0x272/0x2e0 mm/kmsan/kmsan.c:247 > kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:267 > __msan_memcpy+0x43/0x50 mm/kmsan/kmsan_instr.c:116 > pppoe_sendmsg+0xaed/0xb90 drivers/net/ppp/pppoe.c:896 > sock_sendmsg_nosec net/socket.c:652 [inline] > sock_sendmsg net/socket.c:672 [inline] > kernel_sendmsg+0x433/0x440 net/socket.c:692 > sock_no_sendpage+0x235/0x300 net/core/sock.c:2853 > kernel_sendpage net/socket.c:3644 [inline] > sock_sendpage+0x25b/0x2c0 net/socket.c:945 > pipe_to_sendpage+0x38c/0x4c0 fs/splice.c:448 > splice_from_pipe_feed fs/splice.c:502 [inline] >
KMSAN: uninit-value in __skb_flow_dissect (3)
Hello, syzbot found the following issue on: HEAD commit:14525656 compiler.h: reinstate missing KMSAN_INIT git tree: https://github.com/google/kmsan.git master console output: https://syzkaller.appspot.com/x/log.txt?x=154bb20f10 kernel config: https://syzkaller.appspot.com/x/.config?x=c534a9fad6323722 dashboard link: https://syzkaller.appspot.com/bug?extid=051a531e8f1f59cf6dc9 compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) userspace arch: i386 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1394665890 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17adcb6f10 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+051a531e8f1f59cf6...@syzkaller.appspotmail.com batman_adv: batadv0: Interface activated: batadv_slave_1 = BUG: KMSAN: uninit-value in __skb_flow_dissect+0x30f0/0x8440 net/core/flow_dissector.c:1163 CPU: 0 PID: 8524 Comm: syz-executor152 Not tainted 5.8.0-rc5-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+0x1df/0x240 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 __skb_flow_dissect+0x30f0/0x8440 net/core/flow_dissector.c:1163 skb_flow_dissect_flow_keys include/linux/skbuff.h:1310 [inline] ___skb_get_hash net/core/flow_dissector.c:1520 [inline] __skb_get_hash+0x131/0x480 net/core/flow_dissector.c:1586 skb_get_hash include/linux/skbuff.h:1348 [inline] udp_flow_src_port+0xa5/0x690 include/net/udp.h:220 geneve_xmit_skb drivers/net/geneve.c:895 [inline] geneve_xmit+0xdf1/0x2bf0 drivers/net/geneve.c:1005 __netdev_start_xmit include/linux/netdevice.h:4611 [inline] netdev_start_xmit include/linux/netdevice.h:4625 [inline] xmit_one net/core/dev.c:3556 [inline] dev_hard_start_xmit+0x50e/0xa70 net/core/dev.c:3572 __dev_queue_xmit+0x2f8d/0x3b20 net/core/dev.c:4131 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4164 pppoe_sendmsg+0xb43/0xb90 drivers/net/ppp/pppoe.c:900 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] kernel_sendmsg+0x433/0x440 net/socket.c:692 sock_no_sendpage+0x235/0x300 net/core/sock.c:2853 kernel_sendpage net/socket.c:3644 [inline] sock_sendpage+0x25b/0x2c0 net/socket.c:945 pipe_to_sendpage+0x38c/0x4c0 fs/splice.c:448 splice_from_pipe_feed fs/splice.c:502 [inline] __splice_from_pipe+0x565/0xf00 fs/splice.c:626 splice_from_pipe fs/splice.c:661 [inline] generic_splice_sendpage+0x1d5/0x2d0 fs/splice.c:834 do_splice_from fs/splice.c:846 [inline] direct_splice_actor+0x1fd/0x580 fs/splice.c:1016 splice_direct_to_actor+0x6b2/0xf50 fs/splice.c:971 do_splice_direct+0x342/0x580 fs/splice.c:1059 do_sendfile+0x101b/0x1d40 fs/read_write.c:1540 __do_compat_sys_sendfile fs/read_write.c:1622 [inline] __se_compat_sys_sendfile+0x301/0x3c0 fs/read_write.c:1605 __ia32_compat_sys_sendfile+0x56/0x70 fs/read_write.c:1605 do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline] __do_fast_syscall_32+0x2aa/0x400 arch/x86/entry/common.c:477 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7f13549 Code: Bad RIP value. RSP: 002b:ffd520cc EFLAGS: 0217 ORIG_RAX: 00bb RAX: ffda RBX: 0006 RCX: 0005 RDX: RSI: 7fff RDI: 0006 RBP: 2000 R08: R09: R10: R11: R12: R13: R14: R15: Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310 kmsan_memcpy_memmove_metadata+0x272/0x2e0 mm/kmsan/kmsan.c:247 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:267 __msan_memcpy+0x43/0x50 mm/kmsan/kmsan_instr.c:116 pppoe_sendmsg+0xaed/0xb90 drivers/net/ppp/pppoe.c:896 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] kernel_sendmsg+0x433/0x440 net/socket.c:692 sock_no_sendpage+0x235/0x300 net/core/sock.c:2853 kernel_sendpage net/socket.c:3644 [inline] sock_sendpage+0x25b/0x2c0 net/socket.c:945 pipe_to_sendpage+0x38c/0x4c0 fs/splice.c:448 splice_from_pipe_feed fs/splice.c:502 [inline] __splice_from_pipe+0x565/0xf00 fs/splice.c:626 splice_from_pipe fs/splice.c:661 [inline] generic_splice_sendpage+0x1d5/0x2d0 fs/splice.c:834 do_splice_from fs/splice.c:846 [inline] direct_splice_actor+0x1fd/0x580 fs/splice.c:1016 splice_direct_to_actor+0x6b2/0xf50 fs/splice.c:971 do_splice_direct+0x342/0x580 fs/splice.c:1059 do_sendfile+0x101b/0x1d40 fs/read_write.c:1540
