From: Wang Nan <wangnan0@huawei.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: <acme@kernel.org>, <jolsa@kernel.org>, <namhyung@kernel.org>,
<mingo@redhat.com>, <lizefan@huawei.com>, <pi3orama@163.com>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] perf tools: unwind: ensure unwind hooks return negative errorno.
Date: Wed, 1 Apr 2015 20:41:46 +0800 [thread overview]
Message-ID: <551BE78A.6070800@huawei.com> (raw)
In-Reply-To: <20150401121222.GA10820@krava.brq.redhat.com>
On 2015/4/1 20:12, Jiri Olsa wrote:
> On Wed, Apr 01, 2015 at 10:33:12AM +0000, Wang Nan wrote:
>> According to man pages of libunwind, unwind hooks should return
>> 'negative value of one of the unw_error_t error-codes', they are
>> different from generic error code. In addition, access_dso_mem()
>> returns '!(size == sizeof(*data))', compiler never ensure it is
>> negative when failure, which causes libunwind get undesire value
>> when accessing //anon memory.
>>
>> This patch fixes this problem by force returning negative value when
>> error, instead of returning 'ret' itself when it is non-zero.
>
> hum, how about find_proc_info callback.. should it follow the same rules?
>
Yes, but it only returns -EINVAL and dwarf_search_unwind_table(....). The latter
one is part of libunwind so we can trust it returns negative when fail.
> thanks,
> jirka
>
next prev parent reply other threads:[~2015-04-01 12:42 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-01 10:33 [PATCH 0/4] perf tools: introduce --map-adjustment Wang Nan
2015-04-01 10:33 ` [PATCH 1/4] perf tools: unwind: ensure unwind hooks return negative errorno Wang Nan
2015-04-01 12:12 ` Jiri Olsa
2015-04-01 12:41 ` Wang Nan [this message]
2015-04-07 8:30 ` Wang Nan
2015-04-01 10:33 ` [PATCH 2/4] perf tools: introduce machine_map_new to merge mmap/mmap2 processing code Wang Nan
2015-04-01 12:18 ` Jiri Olsa
2015-04-01 14:58 ` Arnaldo Carvalho de Melo
2015-04-01 10:33 ` [PATCH 3/4] perf tools: report: introduce --map-adjustment argument Wang Nan
2015-04-01 13:21 ` Jiri Olsa
2015-04-02 1:15 ` Wang Nan
2015-04-01 14:23 ` pi3orama
2015-04-01 10:33 ` [PATCH 4/4] perf tools: unwinding: try to read from map_adj for a unmapped address Wang Nan
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