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Eric Dumazet 34636d2498 net: memcg: fix lockdep splat in inet_csk_accept() 
commit 06669ea346 upstream.

Locking newsk while still holding the listener lock triggered
a lockdep splat [1]

We can simply move the memcg code after we release the listener lock,
as this can also help if multiple threads are sharing a common listener.

Also fix a typo while reading socket sk_rmem_alloc.

[1]
WARNING: possible recursive locking detected
5.6.0-rc3-syzkaller #0 Not tainted
--------------------------------------------
syz-executor598/9524 is trying to acquire lock:
ffff88808b5b8b90 (sk_lock-AF_INET6){+.+.}, at: lock_sock include/net/sock.h:1541 [inline]
ffff88808b5b8b90 (sk_lock-AF_INET6){+.+.}, at: inet_csk_accept+0x69f/0xd30 net/ipv4/inet_connection_sock.c:492

but task is already holding lock:
ffff88808b5b9590 (sk_lock-AF_INET6){+.+.}, at: lock_sock include/net/sock.h:1541 [inline]
ffff88808b5b9590 (sk_lock-AF_INET6){+.+.}, at: inet_csk_accept+0x8d/0xd30 net/ipv4/inet_connection_sock.c:445

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(sk_lock-AF_INET6);
  lock(sk_lock-AF_INET6);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

1 lock held by syz-executor598/9524:
 #0: ffff88808b5b9590 (sk_lock-AF_INET6){+.+.}, at: lock_sock include/net/sock.h:1541 [inline]
 #0: ffff88808b5b9590 (sk_lock-AF_INET6){+.+.}, at: inet_csk_accept+0x8d/0xd30 net/ipv4/inet_connection_sock.c:445

stack backtrace:
CPU: 0 PID: 9524 Comm: syz-executor598 Not tainted 5.6.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 print_deadlock_bug kernel/locking/lockdep.c:2370 [inline]
 check_deadlock kernel/locking/lockdep.c:2411 [inline]
 validate_chain kernel/locking/lockdep.c:2954 [inline]
 __lock_acquire.cold+0x114/0x288 kernel/locking/lockdep.c:3954
 lock_acquire+0x197/0x420 kernel/locking/lockdep.c:4484
 lock_sock_nested+0xc5/0x110 net/core/sock.c:2947
 lock_sock include/net/sock.h:1541 [inline]
 inet_csk_accept+0x69f/0xd30 net/ipv4/inet_connection_sock.c:492
 inet_accept+0xe9/0x7c0 net/ipv4/af_inet.c:734
 __sys_accept4_file+0x3ac/0x5b0 net/socket.c:1758
 __sys_accept4+0x53/0x90 net/socket.c:1809
 __do_sys_accept4 net/socket.c:1821 [inline]
 __se_sys_accept4 net/socket.c:1818 [inline]
 __x64_sys_accept4+0x93/0xf0 net/socket.c:1818
 do_syscall_64+0xf6/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4445c9
Code: e8 0c 0d 03 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc35b37608 EFLAGS: 00000246 ORIG_RAX: 0000000000000120
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004445c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000306777 R09: 0000000000306777
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000004053d0 R14: 0000000000000000 R15: 0000000000000000

Fixes: d752a49865 ("net: memcg: late association of sock to memcg")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-18 07:14:14 +01:00
arch KVM: SVM: fix up incorrect backport 2020-03-16 09:52:03 +01:00
block block: fix 32 bit overflow in __blkdev_issue_discard() 2020-02-01 09:37:12 +00:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: api - Fix race condition in crypto_spawn_alg 2020-02-11 04:34:05 -08:00
Documentation netfilter: nf_flowtable: fix documentation 2020-03-05 16:42:23 +01:00
drivers bnxt_en: reinitialize IRQs when MTU is modified 2020-03-18 07:14:13 +01:00
firmware Fix built-in early-load Intel microcode alignment 2020-01-23 08:21:29 +01:00
fs fat: fix uninit-memory access for partial initialized inode 2020-03-11 14:15:01 +01:00
include inet_diag: return classid for all socket types 2020-03-18 07:14:11 +01:00
init fork: fix some -Wmissing-prototypes warnings 2019-12-05 09:21:04 +01:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-28 16:38:49 +01:00
kernel cgroup: memcg: net: do not associate sock with unrelated cgroup 2020-03-18 07:14:14 +01:00
lib lib/stackdepot.c: fix global out-of-bounds in stack_slabs 2020-02-28 16:38:55 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm net: memcg: late association of sock to memcg 2020-03-18 07:14:14 +01:00
net net: memcg: fix lockdep splat in inet_csk_accept() 2020-03-18 07:14:14 +01:00
samples samples/bpf: Don't try to remove user's homedir on clean 2020-02-11 04:34:05 -08:00
scripts kbuild: use -S instead of -E for precise cc-option test in Kconfig 2020-02-24 08:34:50 +01:00
security selinux: ensure we cleanup the internal AVC counters on error in avc_update() 2020-02-24 08:34:43 +01:00
sound ASoC: dapm: Correct DAPM handling of active widgets during shutdown 2020-03-11 14:15:09 +01:00
tools selftests: forwarding: use proto icmp for {gretap, ip6gretap}_mac testing 2020-03-11 14:14:51 +01:00
usr kbuild: clean compressed initramfs image 2019-10-07 18:57:16 +02:00
virt KVM: Check for a bad hva before dropping into the ghc slow path 2020-03-05 16:42:21 +01:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 16:38:49 +01:00
Makefile Linux 4.19.110 2020-03-16 09:52:03 +01:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.