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| author | Wen Gu <guwen@linux.alibaba.com> | 2022-01-22 17:43:09 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-01-24 12:06:08 +0000 |
| commit | c0bf3d8a943b6f2e912b7c1de03e2ef28e76f760 (patch) | |
| tree | a834f80fdc8075173abf9c143c2e726d9e634a4a /mm/page_io.c | |
| parent | 3a5d9db7fbdfc8207ddf70d92668ced0ab330701 (diff) | |
| download | linux-c0bf3d8a943b6f2e912b7c1de03e2ef28e76f760.tar.bz2 | |
net/smc: Transitional solution for clcsock race issue
We encountered a crash in smc_setsockopt() and it is caused by
accessing smc->clcsock after clcsock was released.
BUG: kernel NULL pointer dereference, address: 0000000000000020
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 1 PID: 50309 Comm: nginx Kdump: loaded Tainted: G E 5.16.0-rc4+ #53
RIP: 0010:smc_setsockopt+0x59/0x280 [smc]
Call Trace:
<TASK>
__sys_setsockopt+0xfc/0x190
__x64_sys_setsockopt+0x20/0x30
do_syscall_64+0x34/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f16ba83918e
</TASK>
This patch tries to fix it by holding clcsock_release_lock and
checking whether clcsock has already been released before access.
In case that a crash of the same reason happens in smc_getsockopt()
or smc_switch_to_fallback(), this patch also checkes smc->clcsock
in them too. And the caller of smc_switch_to_fallback() will identify
whether fallback succeeds according to the return value.
Fixes: fd57770dd198 ("net/smc: wait for pending work before clcsock release_sock")
Link: https://lore.kernel.org/lkml/5dd7ffd1-28e2-24cc-9442-1defec27375e@linux.ibm.com/T/
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Acked-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'mm/page_io.c')
0 files changed, 0 insertions, 0 deletions