From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Guo, Jia" <jia.guo@intel.com>
Subject: Re: [PATCH V20 2/4] eal: add failure handler mechanism
	for hot plug
Date: Thu, 3 May 2018 11:17:27 +0800
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Cc: "jblunck@infradead.org" <jblunck@infradead.org>,
 "shreyansh.jain@nxp.com" <shreyansh.jain@nxp.com>,
 "dev@dpdk.org" <dev@dpdk.org>, "Zhang, Helin" <helin.zhang@intel.com>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
 "stephen@networkplumber.org" <stephen@networkplumber.org>,
 "Richardson, Bruce" <bruce.richardson@intel.com>,
 "Yigit, Ferruh" <ferruh.yigit@intel.com>,
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 "Wu, Jingjing" <jingjing.wu@intel.com>,
 "thomas@monjalon.net" <thomas@monjalon.net>,
 "motih@mellanox.com" <motih@mellanox.com>,
 "matan@mellanox.com" <matan@mellanox.com>,
 "Van Haaren, Harry" <harry.van.haaren@intel.com>,
 "Tan, Jianfeng" <jianfeng.tan@intel.com>
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On 4/21/2018 12:16 AM, Ananyev, Konstantin wrote:
>>> +
>>> +static void sigbus_handler(int signum __rte_unused, siginfo_t *info,
>>> +				void *ctx __rte_unused)
>>> +{
>>> +	int ret;
>>> +
>>> +	RTE_LOG(ERR, EAL, "SIGBUS error, fault address:%p\n", info->si_addr);
>>> +	ret = dev_uev_failure_process(NULL, info->si_addr);
>> As now you can try to mmap/munmap same address from two or more different threads
>> you probably need some synchronization here.
>> Something simple as spinlock seems to be enough here.
>> We might have one per device or might be even a global one would be ok here.
>>
>>> +	if (!ret)
>>> +		RTE_LOG(DEBUG, EAL,
>>> +			"SIGBUS error is because of hot unplug!\n");
> Also if sigbus handler wasn't able to fix things - failure addr doesn't belong to
> any devices, or remaping fails - we probably should invoke previously installed handler
> or just apply default action.
> Konstantin
i think just exception here by exit for apply default action, and info 
that is a normal sigbus error should be ok.
>>> +}
>>> +