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authorEric Dumazet <edumazet@google.com>2019-09-24 12:29:34 -0700
committerDavid S. Miller <davem@davemloft.net>2019-09-27 10:27:14 +0200
commit0355d6c1d591b8f9e281783ec0cf95fbed893194 (patch)
treeca61bbe3192364ffb413638073f63925fd5bcb8d /net/kcm
parentnet: ethernet: stmmac: Fix signedness bug in ipq806x_gmac_of_parse() (diff)
downloadlinux-dev-0355d6c1d591b8f9e281783ec0cf95fbed893194.tar.xz
linux-dev-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')
-rw-r--r--net/kcm/kcmsock.c6
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)