From b82b566a46ef61f26f461f0c55e6588b2cc93384 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 12 Jun 2012 00:47:58 +0200 Subject: [PATCH] NFC: Return from rawsock_release when sk is NULL commit 03e934f620101ca2cfc9383bd76172dd3e1f8567 upstream. Sasha Levin reported following panic : [ 2136.383310] BUG: unable to handle kernel NULL pointer dereference at 00000000000003b0 [ 2136.384022] IP: [] __lock_acquire+0xc0/0x4b0 [ 2136.384022] PGD 131c4067 PUD 11c0c067 PMD 0 [ 2136.388106] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 2136.388106] CPU 1 [ 2136.388106] Pid: 24855, comm: trinity-child1 Tainted: G W 3.5.0-rc2-sasha-00015-g7b268f7 #374 [ 2136.388106] RIP: 0010:[] [] __lock_acquire+0xc0/0x4b0 [ 2136.388106] RSP: 0018:ffff8800130b3ca8 EFLAGS: 00010046 [ 2136.388106] RAX: 0000000000000086 RBX: ffff88001186b000 RCX: 0000000000000000 [ 2136.388106] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 2136.388106] RBP: ffff8800130b3d08 R08: 0000000000000001 R09: 0000000000000000 [ 2136.388106] R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000002 [ 2136.388106] R13: 00000000000003b0 R14: 0000000000000000 R15: 0000000000000000 [ 2136.388106] FS: 00007fa5b1bd4700(0000) GS:ffff88001b800000(0000) knlGS:0000000000000000 [ 2136.388106] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2136.388106] CR2: 00000000000003b0 CR3: 0000000011d1f000 CR4: 00000000000406e0 [ 2136.388106] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2136.388106] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 2136.388106] Process trinity-child1 (pid: 24855, threadinfo ffff8800130b2000, task ffff88001186b000) [ 2136.388106] Stack: [ 2136.388106] ffff8800130b3cd8 ffffffff81121785 ffffffff81236774 000080d000000001 [ 2136.388106] ffff88001b9d6c00 00000000001d6c00 ffffffff130b3d08 ffff88001186b000 [ 2136.388106] 0000000000000000 0000000000000002 0000000000000000 0000000000000000 [ 2136.388106] Call Trace: [ 2136.388106] [] ? sched_clock_local+0x25/0x90 [ 2136.388106] [] ? get_empty_filp+0x74/0x220 [ 2136.388106] [] lock_acquire+0x18a/0x1e0 [ 2136.388106] [] ? rawsock_release+0x4f/0xa0 [ 2136.388106] [] _raw_write_lock_bh+0x40/0x80 [ 2136.388106] [] ? rawsock_release+0x4f/0xa0 [ 2136.388106] [] rawsock_release+0x4f/0xa0 [ 2136.388106] [] sock_release+0x18/0x70 [ 2136.388106] [] sock_close+0x29/0x30 [ 2136.388106] [] __fput+0x11a/0x2c0 [ 2136.388106] [] fput+0x15/0x20 [ 2136.388106] [] sys_accept4+0x1b4/0x200 [ 2136.388106] [] ? _raw_spin_unlock_irq+0x4c/0x80 [ 2136.388106] [] ? _raw_spin_unlock_irq+0x59/0x80 [ 2136.388106] [] ? sysret_check+0x22/0x5d [ 2136.388106] [] sys_accept+0xb/0x10 [ 2136.388106] [] system_call_fastpath+0x16/0x1b [ 2136.388106] Code: ec 04 00 0f 85 ea 03 00 00 be d5 0b 00 00 48 c7 c7 8a c1 40 84 e8 b1 a5 f8 ff 31 c0 e9 d4 03 00 00 66 2e 0f 1f 84 00 00 00 00 00 <49> 81 7d 00 60 73 5e 85 b8 01 00 00 00 44 0f 44 e0 83 fe 01 77 [ 2136.388106] RIP [] __lock_acquire+0xc0/0x4b0 [ 2136.388106] RSP [ 2136.388106] CR2: 00000000000003b0 [ 2136.388106] ---[ end trace 6d450e935ee18982 ]--- [ 2136.388106] Kernel panic - not syncing: Fatal exception in interrupt rawsock_release() should test if sock->sk is NULL before calling sock_orphan()/sock_put() Reported-by: Sasha Levin Tested-by: Sasha Levin Signed-off-by: Eric Dumazet Signed-off-by: Samuel Ortiz [bwh: Backported to 3.2: keep using nfc_dbg(), not pr_debug()] Signed-off-by: Ben Hutchings --- net/nfc/rawsock.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/nfc/rawsock.c b/net/nfc/rawsock.c index ee7b2b365ef2..7a167fce319c 100644 --- a/net/nfc/rawsock.c +++ b/net/nfc/rawsock.c @@ -52,7 +52,10 @@ static int rawsock_release(struct socket *sock) { struct sock *sk = sock->sk; - nfc_dbg("sock=%p", sock); + nfc_dbg("sock=%p sk=%p", sock, sk); + + if (!sk) + return 0; sock_orphan(sk); sock_put(sk); -- 2.39.2