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![]() 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:
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.. | ||
af_smc.c | ||
Kconfig | ||
Makefile | ||
smc.h | ||
smc_cdc.c | ||
smc_cdc.h | ||
smc_clc.c | ||
smc_clc.h | ||
smc_close.c | ||
smc_close.h | ||
smc_core.c | ||
smc_core.h | ||
smc_diag.c | ||
smc_ib.c | ||
smc_ib.h | ||
smc_ism.c | ||
smc_ism.h | ||
smc_llc.c | ||
smc_llc.h | ||
smc_netlink.c | ||
smc_netlink.h | ||
smc_netns.h | ||
smc_pnet.c | ||
smc_pnet.h | ||
smc_rx.c | ||
smc_rx.h | ||
smc_stats.c | ||
smc_stats.h | ||
smc_tracepoint.c | ||
smc_tracepoint.h | ||
smc_tx.c | ||
smc_tx.h | ||
smc_wr.c | ||
smc_wr.h |