af_key: do not use GFP_KERNEL in atomic contexts
pfkey_broadcast() might be called from non process contexts,
we can not use GFP_KERNEL in these cases [1].
This patch partially reverts commit ba51b6be38 ("net: Fix RCU splat in
af_key"), only keeping the GFP_ATOMIC forcing under rcu_read_lock()
section.
[1] : syzkaller reported :
in_atomic(): 1, irqs_disabled(): 0, pid: 2932, name: syzkaller183439
3 locks held by syzkaller183439/2932:
#0: (&net->xfrm.xfrm_cfg_mutex){+.+.+.}, at: [<ffffffff83b43888>] pfkey_sendmsg+0x4c8/0x9f0 net/key/af_key.c:3649
#1: (&pfk->dump_lock){+.+.+.}, at: [<ffffffff83b467f6>] pfkey_do_dump+0x76/0x3f0 net/key/af_key.c:293
#2: (&(&net->xfrm.xfrm_policy_lock)->rlock){+...+.}, at: [<ffffffff83957632>] spin_lock_bh include/linux/spinlock.h:304 [inline]
#2: (&(&net->xfrm.xfrm_policy_lock)->rlock){+...+.}, at: [<ffffffff83957632>] xfrm_policy_walk+0x192/0xa30 net/xfrm/xfrm_policy.c:1028
CPU: 0 PID: 2932 Comm: syzkaller183439 Not tainted 4.13.0-rc4+ #24
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:16 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:52
___might_sleep+0x2b2/0x470 kernel/sched/core.c:5994
__might_sleep+0x95/0x190 kernel/sched/core.c:5947
slab_pre_alloc_hook mm/slab.h:416 [inline]
slab_alloc mm/slab.c:3383 [inline]
kmem_cache_alloc+0x24b/0x6e0 mm/slab.c:3559
skb_clone+0x1a0/0x400 net/core/skbuff.c:1037
pfkey_broadcast_one+0x4b2/0x6f0 net/key/af_key.c:207
pfkey_broadcast+0x4ba/0x770 net/key/af_key.c:281
dump_sp+0x3d6/0x500 net/key/af_key.c:2685
xfrm_policy_walk+0x2f1/0xa30 net/xfrm/xfrm_policy.c:1042
pfkey_dump_sp+0x42/0x50 net/key/af_key.c:2695
pfkey_do_dump+0xaa/0x3f0 net/key/af_key.c:299
pfkey_spddump+0x1a0/0x210 net/key/af_key.c:2722
pfkey_process+0x606/0x710 net/key/af_key.c:2814
pfkey_sendmsg+0x4d6/0x9f0 net/key/af_key.c:3650
sock_sendmsg_nosec net/socket.c:633 [inline]
sock_sendmsg+0xca/0x110 net/socket.c:643
___sys_sendmsg+0x755/0x890 net/socket.c:2035
__sys_sendmsg+0xe5/0x210 net/socket.c:2069
SYSC_sendmsg net/socket.c:2080 [inline]
SyS_sendmsg+0x2d/0x50 net/socket.c:2076
entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x445d79
RSP: 002b:00007f32447c1dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000445d79
RDX: 0000000000000000 RSI: 000000002023dfc8 RDI: 0000000000000008
RBP: 0000000000000086 R08: 00007f32447c2700 R09: 00007f32447c2700
R10: 00007f32447c2700 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffe33edec4f R14: 00007f32447c29c0 R15: 0000000000000000
Fixes: ba51b6be38 ("net: Fix RCU splat in af_key")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: David Ahern <dsa@cumulusnetworks.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
36f41f8fc6