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| author | Eric Dumazet <edumazet@google.com> | 2019-05-13 09:38:55 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-05-13 09:53:42 -0700 |
| commit | b1c17a9a353878602fd5bfe9103e4afe5e9a3f96 (patch) | |
| tree | 51800af84a98c97588f278596b769523976e53d0 /net/core | |
| parent | a9b8a2b39ce65df45687cf9ef648885c2a99fe75 (diff) | |
| download | linux-b1c17a9a353878602fd5bfe9103e4afe5e9a3f96.tar.bz2 | |
flow_dissector: disable preemption around BPF calls
Various things in eBPF really require us to disable preemption
before running an eBPF program.
syzbot reported :
BUG: assuming atomic context at net/core/flow_dissector.c:737
in_atomic(): 0, irqs_disabled(): 0, pid: 24710, name: syz-executor.3
2 locks held by syz-executor.3/24710:
#0: 00000000e81a4bf1 (&tfile->napi_mutex){+.+.}, at: tun_get_user+0x168e/0x3ff0 drivers/net/tun.c:1850
#1: 00000000254afebd (rcu_read_lock){....}, at: __skb_flow_dissect+0x1e1/0x4bb0 net/core/flow_dissector.c:822
CPU: 1 PID: 24710 Comm: syz-executor.3 Not tainted 5.1.0+ #6
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+0x172/0x1f0 lib/dump_stack.c:113
__cant_sleep kernel/sched/core.c:6165 [inline]
__cant_sleep.cold+0xa3/0xbb kernel/sched/core.c:6142
bpf_flow_dissect+0xfe/0x390 net/core/flow_dissector.c:737
__skb_flow_dissect+0x362/0x4bb0 net/core/flow_dissector.c:853
skb_flow_dissect_flow_keys_basic include/linux/skbuff.h:1322 [inline]
skb_probe_transport_header include/linux/skbuff.h:2500 [inline]
skb_probe_transport_header include/linux/skbuff.h:2493 [inline]
tun_get_user+0x2cfe/0x3ff0 drivers/net/tun.c:1940
tun_chr_write_iter+0xbd/0x156 drivers/net/tun.c:2037
call_write_iter include/linux/fs.h:1872 [inline]
do_iter_readv_writev+0x5fd/0x900 fs/read_write.c:693
do_iter_write fs/read_write.c:970 [inline]
do_iter_write+0x184/0x610 fs/read_write.c:951
vfs_writev+0x1b3/0x2f0 fs/read_write.c:1015
do_writev+0x15b/0x330 fs/read_write.c:1058
__do_sys_writev fs/read_write.c:1131 [inline]
__se_sys_writev fs/read_write.c:1128 [inline]
__x64_sys_writev+0x75/0xb0 fs/read_write.c:1128
do_syscall_64+0x103/0x670 arch/x86/entry/common.c:298
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fixes: d58e468b1112 ("flow_dissector: implements flow dissector BPF hook")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Petar Penkov <ppenkov@google.com>
Cc: Stanislav Fomichev <sdf@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/flow_dissector.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 9ca784c592ac..548f39dde307 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -734,7 +734,9 @@ bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx, flow_keys->nhoff = nhoff; flow_keys->thoff = flow_keys->nhoff; + preempt_disable(); result = BPF_PROG_RUN(prog, ctx); + preempt_enable(); flow_keys->nhoff = clamp_t(u16, flow_keys->nhoff, nhoff, hlen); flow_keys->thoff = clamp_t(u16, flow_keys->thoff, |