9d6d7f1cb6
wait_for_unix_gc() reads unix_tot_inflight & gc_in_progress without synchronization. Adds READ_ONCE()/WRITE_ONCE() and their associated comments to better document the intent. BUG: KCSAN: data-race in unix_inflight / wait_for_unix_gc write to 0xffffffff86e2b7c0 of 4 bytes by task 9380 on cpu 0: unix_inflight+0x1e8/0x260 net/unix/scm.c:63 unix_attach_fds+0x10c/0x1e0 net/unix/scm.c:121 unix_scm_to_skb net/unix/af_unix.c:1674 [inline] unix_dgram_sendmsg+0x679/0x16b0 net/unix/af_unix.c:1817 unix_seqpacket_sendmsg+0xcc/0x110 net/unix/af_unix.c:2258 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2409 ___sys_sendmsg net/socket.c:2463 [inline] __sys_sendmmsg+0x267/0x4c0 net/socket.c:2549 __do_sys_sendmmsg net/socket.c:2578 [inline] __se_sys_sendmmsg net/socket.c:2575 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2575 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffffffff86e2b7c0 of 4 bytes by task 9375 on cpu 1: wait_for_unix_gc+0x24/0x160 net/unix/garbage.c:196 unix_dgram_sendmsg+0x8e/0x16b0 net/unix/af_unix.c:1772 unix_seqpacket_sendmsg+0xcc/0x110 net/unix/af_unix.c:2258 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2409 ___sys_sendmsg net/socket.c:2463 [inline] __sys_sendmmsg+0x267/0x4c0 net/socket.c:2549 __do_sys_sendmmsg net/socket.c:2578 [inline] __se_sys_sendmmsg net/socket.c:2575 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2575 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x00000002 -> 0x00000004 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 9375 Comm: syz-executor.1 Not tainted 5.16.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 9915672d4127 ("af_unix: limit unix_tot_inflight") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Link: https://lore.kernel.org/r/20220114164328.2038499-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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.
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.