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Linux kernel source tree
syzbot hit a use-after-free[1] which is caused because the bridge doesn't
make sure that all previous garbage has been collected when removing a
port. What happens is:
CPU 1 CPU 2
start gc cycle remove port
acquire gc lock first
wait for lock
call br_multicasg_gc() directly
acquire lock now but free port
the port can be freed
while grp timers still
running
Make sure all previous gc cycles have finished by using flush_work before
freeing the port.
[1]
BUG: KASAN: slab-use-after-free in br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861
Read of size 8 at addr ffff888071d6d000 by task syz.5.1232/9699
CPU: 1 PID: 9699 Comm: syz.5.1232 Not tainted 6.10.0-rc5-syzkaller-00021-g24ca36a562d6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861
call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792
expire_timers kernel/time/timer.c:1843 [inline]
__run_timers+0x74b/0xaf0 kernel/time/timer.c:2417
__run_timer_base kernel/time/timer.c:2428 [inline]
__run_timer_base kernel/time/timer.c:2421 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2437
Reported-by: syzbot+263426984509be19c9a0@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=263426984509be19c9a0
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| 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 reStructuredText 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.