mainlining shenanigans
4a2b285e7e
Fix the data-race reported by syzbot [1]
Issue here is that igmp_ifc_timer_expire() can update in_dev->mr_ifc_count
while another change just occured from another context.
in_dev->mr_ifc_count is only 8bit wide, so the race had little
consequences.
[1]
BUG: KCSAN: data-race in igmp_ifc_event / igmp_ifc_timer_expire
write to 0xffff8881051e3062 of 1 bytes by task 12547 on cpu 0:
igmp_ifc_event+0x1d5/0x290 net/ipv4/igmp.c:821
igmp_group_added+0x462/0x490 net/ipv4/igmp.c:1356
____ip_mc_inc_group+0x3ff/0x500 net/ipv4/igmp.c:1461
__ip_mc_join_group+0x24d/0x2c0 net/ipv4/igmp.c:2199
ip_mc_join_group_ssm+0x20/0x30 net/ipv4/igmp.c:2218
do_ip_setsockopt net/ipv4/ip_sockglue.c:1285 [inline]
ip_setsockopt+0x1827/0x2a80 net/ipv4/ip_sockglue.c:1423
tcp_setsockopt+0x8c/0xa0 net/ipv4/tcp.c:3657
sock_common_setsockopt+0x5d/0x70 net/core/sock.c:3362
__sys_setsockopt+0x18f/0x200 net/socket.c:2159
__do_sys_setsockopt net/socket.c:2170 [inline]
__se_sys_setsockopt net/socket.c:2167 [inline]
__x64_sys_setsockopt+0x62/0x70 net/socket.c:2167
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
read to 0xffff8881051e3062 of 1 bytes by interrupt on cpu 1:
igmp_ifc_timer_expire+0x706/0xa30 net/ipv4/igmp.c:808
call_timer_fn+0x2e/0x1d0 kernel/time/timer.c:1419
expire_timers+0x135/0x250 kernel/time/timer.c:1464
__run_timers+0x358/0x420 kernel/time/timer.c:1732
run_timer_softirq+0x19/0x30 kernel/time/timer.c:1745
__do_softirq+0x12c/0x26e kernel/softirq.c:558
invoke_softirq kernel/softirq.c:432 [inline]
__irq_exit_rcu+0x9a/0xb0 kernel/softirq.c:636
sysvec_apic_timer_interrupt+0x69/0x80 arch/x86/kernel/apic/apic.c:1100
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
console_unlock+0x8e8/0xb30 kernel/printk/printk.c:2646
vprintk_emit+0x125/0x3d0 kernel/printk/printk.c:2174
vprintk_default+0x22/0x30 kernel/printk/printk.c:2185
vprintk+0x15a/0x170 kernel/printk/printk_safe.c:392
printk+0x62/0x87 kernel/printk/printk.c:2216
selinux_netlink_send+0x399/0x400 security/selinux/hooks.c:6041
security_netlink_send+0x42/0x90 security/security.c:2070
netlink_sendmsg+0x59e/0x7c0 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:703 [inline]
sock_sendmsg net/socket.c:723 [inline]
____sys_sendmsg+0x360/0x4d0 net/socket.c:2392
___sys_sendmsg net/socket.c:2446 [inline]
__sys_sendmsg+0x1ed/0x270 net/socket.c:2475
__do_sys_sendmsg net/socket.c:2484 [inline]
__se_sys_sendmsg net/socket.c:2482 [inline]
__x64_sys_sendmsg+0x42/0x50 net/socket.c:2482
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0x01 -> 0x02
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12539 Comm: syz-executor.1 Not tainted 5.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.
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.