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| author | Eric Dumazet <edumazet@google.com> | 2019-09-24 12:29:34 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-09-27 10:27:14 +0200 |
| commit | 0355d6c1d591b8f9e281783ec0cf95fbed893194 (patch) | |
| tree | ca61bbe3192364ffb413638073f63925fd5bcb8d /net/kcm/kcmsock.c | |
| parent | 231042181dc9d6122c6faba64e99ccb25f13cc6c (diff) | |
| download | lwn-0355d6c1d591b8f9e281783ec0cf95fbed893194.tar.gz lwn-0355d6c1d591b8f9e281783ec0cf95fbed893194.zip | |
kcm: disable preemption in kcm_parse_func_strparser()
After commit a2c11b034142 ("kcm: use BPF_PROG_RUN")
syzbot easily triggers the warning in cant_sleep().
As explained in commit 6cab5e90ab2b ("bpf: run bpf programs
with preemption disabled") we need to disable preemption before
running bpf programs.
BUG: assuming atomic context at net/kcm/kcmsock.c:382
in_atomic(): 0, irqs_disabled(): 0, pid: 7, name: kworker/u4:0
3 locks held by kworker/u4:0/7:
#0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline]
#0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
#0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
#0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline]
#0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline]
#0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2240
#1: ffff8880a989fdc0 ((work_completion)(&strp->work)){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2244
#2: ffff888098998d10 (sk_lock-AF_INET){+.+.}, at: lock_sock include/net/sock.h:1522 [inline]
#2: ffff888098998d10 (sk_lock-AF_INET){+.+.}, at: strp_sock_lock+0x2e/0x40 net/strparser/strparser.c:440
CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: kstrp strp_work
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:6826 [inline]
__cant_sleep.cold+0xa4/0xbc kernel/sched/core.c:6803
kcm_parse_func_strparser+0x54/0x200 net/kcm/kcmsock.c:382
__strp_recv+0x5dc/0x1b20 net/strparser/strparser.c:221
strp_recv+0xcf/0x10b net/strparser/strparser.c:343
tcp_read_sock+0x285/0xa00 net/ipv4/tcp.c:1639
strp_read_sock+0x14d/0x200 net/strparser/strparser.c:366
do_strp_work net/strparser/strparser.c:414 [inline]
strp_work+0xe3/0x130 net/strparser/strparser.c:423
process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
Fixes: a2c11b034142 ("kcm: use BPF_PROG_RUN")
Fixes: 6cab5e90ab2b ("bpf: run bpf programs with preemption disabled")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/kcm/kcmsock.c')
| -rw-r--r-- | net/kcm/kcmsock.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c index 8f12f5c6ab87..ea9e73428ed9 100644 --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -378,8 +378,12 @@ static int kcm_parse_func_strparser(struct strparser *strp, struct sk_buff *skb) { struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp); struct bpf_prog *prog = psock->bpf_prog; + int res; - return BPF_PROG_RUN(prog, skb); + preempt_disable(); + res = BPF_PROG_RUN(prog, skb); + preempt_enable(); + return res; } static int kcm_read_sock_done(struct strparser *strp, int err) |