Revision 49054556289e8787501630b7c7a9d407da02e296 authored by Paolo Abeni on 29 September 2021, 09:59:17 UTC, committed by David S. Miller on 30 September 2021, 12:06:47 UTC
Syzkaller reported a false positive deadlock involving the nl socket lock and the subflow socket lock: MPTCP: kernel_bind error, err=-98 ============================================ WARNING: possible recursive locking detected 5.15.0-rc1-syzkaller #0 Not tainted -------------------------------------------- syz-executor998/6520 is trying to acquire lock: ffff8880795718a0 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close+0x267/0x7b0 net/mptcp/protocol.c:2738 but task is already holding lock: ffff8880787c8c60 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1612 [inline] ffff8880787c8c60 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close+0x23/0x7b0 net/mptcp/protocol.c:2720 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(k-sk_lock-AF_INET); lock(k-sk_lock-AF_INET); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by syz-executor998/6520: #0: ffffffff8d176c50 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:802 #1: ffffffff8d176d08 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline] #1: ffffffff8d176d08 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x3e0/0x580 net/netlink/genetlink.c:790 #2: ffff8880787c8c60 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1612 [inline] #2: ffff8880787c8c60 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close+0x23/0x7b0 net/mptcp/protocol.c:2720 stack backtrace: CPU: 1 PID: 6520 Comm: syz-executor998 Not tainted 5.15.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2944 [inline] check_deadlock kernel/locking/lockdep.c:2987 [inline] validate_chain kernel/locking/lockdep.c:3776 [inline] __lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 lock_sock_fast+0x36/0x100 net/core/sock.c:3229 mptcp_close+0x267/0x7b0 net/mptcp/protocol.c:2738 inet_release+0x12e/0x280 net/ipv4/af_inet.c:431 __sock_release net/socket.c:649 [inline] sock_release+0x87/0x1b0 net/socket.c:677 mptcp_pm_nl_create_listen_socket+0x238/0x2c0 net/mptcp/pm_netlink.c:900 mptcp_nl_cmd_add_addr+0x359/0x930 net/mptcp/pm_netlink.c:1170 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline] genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 sock_no_sendpage+0x101/0x150 net/core/sock.c:2980 kernel_sendpage.part.0+0x1a0/0x340 net/socket.c:3504 kernel_sendpage net/socket.c:3501 [inline] sock_sendpage+0xe5/0x140 net/socket.c:1003 pipe_to_sendpage+0x2ad/0x380 fs/splice.c:364 splice_from_pipe_feed fs/splice.c:418 [inline] __splice_from_pipe+0x43e/0x8a0 fs/splice.c:562 splice_from_pipe fs/splice.c:597 [inline] generic_splice_sendpage+0xd4/0x140 fs/splice.c:746 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x110/0x180 fs/splice.c:936 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891 do_splice_direct+0x1b3/0x280 fs/splice.c:979 do_sendfile+0xae9/0x1240 fs/read_write.c:1249 __do_sys_sendfile64 fs/read_write.c:1314 [inline] __se_sys_sendfile64 fs/read_write.c:1300 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1300 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f215cb69969 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc96bb3868 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f215cbad072 RCX: 00007f215cb69969 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 0000000000000000 R08: 00007ffc96bb3a08 R09: 00007ffc96bb3a08 R10: 0000000100000002 R11: 0000000000000246 R12: 00007ffc96bb387c R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000 the problem originates from uncorrect lock annotation in the mptcp code and is only visible since commit 2dcb96bacce3 ("net: core: Correct the sock::sk_lock.owned lockdep annotations"), but is present since the port-based endpoint support initial implementation. This patch addresses the issue introducing a nested variant of lock_sock_fast() and using it in the relevant code path. Fixes: 1729cf186d8a ("mptcp: create the listening socket for new port") Fixes: 2dcb96bacce3 ("net: core: Correct the sock::sk_lock.owned lockdep annotations") Suggested-by: Thomas Gleixner <tglx@linutronix.de> Reported-and-tested-by: syzbot+1dd53f7a89b299d59eaf@syzkaller.appspotmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent d88fd1b
mmx.c
// SPDX-License-Identifier: GPL-2.0-or-later
/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright 2002 H. Peter Anvin - All Rights Reserved
*
* ----------------------------------------------------------------------- */
/*
* raid6/mmx.c
*
* MMX implementation of RAID-6 syndrome functions
*/
#ifdef CONFIG_X86_32
#include <linux/raid/pq.h>
#include "x86.h"
/* Shared with raid6/sse1.c */
const struct raid6_mmx_constants {
u64 x1d;
} raid6_mmx_constants = {
0x1d1d1d1d1d1d1d1dULL,
};
static int raid6_have_mmx(void)
{
/* Not really "boot_cpu" but "all_cpus" */
return boot_cpu_has(X86_FEATURE_MMX);
}
/*
* Plain MMX implementation
*/
static void raid6_mmx1_gen_syndrome(int disks, size_t bytes, void **ptrs)
{
u8 **dptr = (u8 **)ptrs;
u8 *p, *q;
int d, z, z0;
z0 = disks - 3; /* Highest data disk */
p = dptr[z0+1]; /* XOR parity */
q = dptr[z0+2]; /* RS syndrome */
kernel_fpu_begin();
asm volatile("movq %0,%%mm0" : : "m" (raid6_mmx_constants.x1d));
asm volatile("pxor %mm5,%mm5"); /* Zero temp */
for ( d = 0 ; d < bytes ; d += 8 ) {
asm volatile("movq %0,%%mm2" : : "m" (dptr[z0][d])); /* P[0] */
asm volatile("movq %mm2,%mm4"); /* Q[0] */
for ( z = z0-1 ; z >= 0 ; z-- ) {
asm volatile("movq %0,%%mm6" : : "m" (dptr[z][d]));
asm volatile("pcmpgtb %mm4,%mm5");
asm volatile("paddb %mm4,%mm4");
asm volatile("pand %mm0,%mm5");
asm volatile("pxor %mm5,%mm4");
asm volatile("pxor %mm5,%mm5");
asm volatile("pxor %mm6,%mm2");
asm volatile("pxor %mm6,%mm4");
}
asm volatile("movq %%mm2,%0" : "=m" (p[d]));
asm volatile("pxor %mm2,%mm2");
asm volatile("movq %%mm4,%0" : "=m" (q[d]));
asm volatile("pxor %mm4,%mm4");
}
kernel_fpu_end();
}
const struct raid6_calls raid6_mmxx1 = {
raid6_mmx1_gen_syndrome,
NULL, /* XOR not yet implemented */
raid6_have_mmx,
"mmxx1",
0
};
/*
* Unrolled-by-2 MMX implementation
*/
static void raid6_mmx2_gen_syndrome(int disks, size_t bytes, void **ptrs)
{
u8 **dptr = (u8 **)ptrs;
u8 *p, *q;
int d, z, z0;
z0 = disks - 3; /* Highest data disk */
p = dptr[z0+1]; /* XOR parity */
q = dptr[z0+2]; /* RS syndrome */
kernel_fpu_begin();
asm volatile("movq %0,%%mm0" : : "m" (raid6_mmx_constants.x1d));
asm volatile("pxor %mm5,%mm5"); /* Zero temp */
asm volatile("pxor %mm7,%mm7"); /* Zero temp */
for ( d = 0 ; d < bytes ; d += 16 ) {
asm volatile("movq %0,%%mm2" : : "m" (dptr[z0][d])); /* P[0] */
asm volatile("movq %0,%%mm3" : : "m" (dptr[z0][d+8]));
asm volatile("movq %mm2,%mm4"); /* Q[0] */
asm volatile("movq %mm3,%mm6"); /* Q[1] */
for ( z = z0-1 ; z >= 0 ; z-- ) {
asm volatile("pcmpgtb %mm4,%mm5");
asm volatile("pcmpgtb %mm6,%mm7");
asm volatile("paddb %mm4,%mm4");
asm volatile("paddb %mm6,%mm6");
asm volatile("pand %mm0,%mm5");
asm volatile("pand %mm0,%mm7");
asm volatile("pxor %mm5,%mm4");
asm volatile("pxor %mm7,%mm6");
asm volatile("movq %0,%%mm5" : : "m" (dptr[z][d]));
asm volatile("movq %0,%%mm7" : : "m" (dptr[z][d+8]));
asm volatile("pxor %mm5,%mm2");
asm volatile("pxor %mm7,%mm3");
asm volatile("pxor %mm5,%mm4");
asm volatile("pxor %mm7,%mm6");
asm volatile("pxor %mm5,%mm5");
asm volatile("pxor %mm7,%mm7");
}
asm volatile("movq %%mm2,%0" : "=m" (p[d]));
asm volatile("movq %%mm3,%0" : "=m" (p[d+8]));
asm volatile("movq %%mm4,%0" : "=m" (q[d]));
asm volatile("movq %%mm6,%0" : "=m" (q[d+8]));
}
kernel_fpu_end();
}
const struct raid6_calls raid6_mmxx2 = {
raid6_mmx2_gen_syndrome,
NULL, /* XOR not yet implemented */
raid6_have_mmx,
"mmxx2",
0
};
#endif
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