mirror of
https://github.com/torvalds/linux.git
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A mirror of the official Linux kernel repository just in case
71a8508402
The bpfilter.ko module can be removed while functions of the bpfilter.ko
are executing. so panic can occurred. in order to protect that, locks can
be used. a bpfilter_lock protects routines in the
__bpfilter_process_sockopt() but it's not enough because __exit routine
can be executed concurrently.
Now, the bpfilter_umh can not run in parallel.
So, the module do not removed while it's being used and it do not
double-create UMH process.
The members of the umh_info and the bpfilter_umh_ops are protected by
the bpfilter_umh_ops.lock.
test commands:
while :
do
iptables -I FORWARD -m string --string ap --algo kmp &
modprobe -rv bpfilter &
done
splat looks like:
[ 298.623435] BUG: unable to handle kernel paging request at fffffbfff807440b
[ 298.628512] #PF error: [normal kernel read fault]
[ 298.633018] PGD 124327067 P4D 124327067 PUD 11c1a3067 PMD 119eb2067 PTE 0
[ 298.638859] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[ 298.638859] CPU: 0 PID: 2997 Comm: iptables Not tainted 4.20.0+ #154
[ 298.638859] RIP: 0010:__mutex_lock+0x6b9/0x16a0
[ 298.638859] Code: c0 00 00 e8 89 82 ff ff 80 bd 8f fc ff ff 00 0f 85 d9 05 00 00 48 8b 85 80 fc ff ff 48 bf 00 00 00 00 00 fc ff df 48 c1 e8 03 <80> 3c 38 00 0f 85 1d 0e 00 00 48 8b 85 c8 fc ff ff 49 39 47 58 c6
[ 298.638859] RSP: 0018:ffff88810e7777a0 EFLAGS: 00010202
[ 298.638859] RAX: 1ffffffff807440b RBX: ffff888111bd4d80 RCX: 0000000000000000
[ 298.638859] RDX: 1ffff110235ff806 RSI: ffff888111bd5538 RDI: dffffc0000000000
[ 298.638859] RBP: ffff88810e777b30 R08: 0000000080000002 R09: 0000000000000000
[ 298.638859] R10: 0000000000000000 R11: 0000000000000000 R12: fffffbfff168a42c
[ 298.638859] R13: ffff888111bd4d80 R14: ffff8881040e9a05 R15: ffffffffc03a2000
[ 298.638859] FS: 00007f39e3758700(0000) GS:ffff88811ae00000(0000) knlGS:0000000000000000
[ 298.638859] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 298.638859] CR2: fffffbfff807440b CR3: 000000011243e000 CR4: 00000000001006f0
[ 298.638859] Call Trace:
[ 298.638859] ? mutex_lock_io_nested+0x1560/0x1560
[ 298.638859] ? kasan_kmalloc+0xa0/0xd0
[ 298.638859] ? kmem_cache_alloc+0x1c2/0x260
[ 298.638859] ? __alloc_file+0x92/0x3c0
[ 298.638859] ? alloc_empty_file+0x43/0x120
[ 298.638859] ? alloc_file_pseudo+0x220/0x330
[ 298.638859] ? sock_alloc_file+0x39/0x160
[ 298.638859] ? __sys_socket+0x113/0x1d0
[ 298.638859] ? __x64_sys_socket+0x6f/0xb0
[ 298.638859] ? do_syscall_64+0x138/0x560
[ 298.638859] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 298.638859] ? __alloc_file+0x92/0x3c0
[ 298.638859] ? init_object+0x6b/0x80
[ 298.638859] ? cyc2ns_read_end+0x10/0x10
[ 298.638859] ? cyc2ns_read_end+0x10/0x10
[ 298.638859] ? hlock_class+0x140/0x140
[ 298.638859] ? sched_clock_local+0xd4/0x140
[ 298.638859] ? sched_clock_local+0xd4/0x140
[ 298.638859] ? check_flags.part.37+0x440/0x440
[ 298.638859] ? __lock_acquire+0x4f90/0x4f90
[ 298.638859] ? set_rq_offline.part.89+0x140/0x140
[ ... ]
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| 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.