Messages in this thread | | | Date | Fri, 20 Feb 2015 23:05:15 -0500 | From | Chris Metcalf <> | Subject | Re: [PATCH] compat: Fix endian issue in union sigval |
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On 2/14/2015 6:22 AM, Catalin Marinas wrote: > 1. user populates sival_int compat_sigevent and invokes > compat_sys_mq_notify() > 2. kernel get_compat_sigevent() copies compat_sigevent into the native > sigevent. compat and native sival_int are the same, no problem so > far. The other half of 64-bit sival_ptr is zeroed by a memset in this > function (this other half can be top or bottom, depending on > endianness) > 3. signal is about to be delivered to user via arch code. The > compat_ptr(from->si_ptr) conversion always takes the least > significant part of the native si_ptr. On big endian 64-bit, this is > zero because get_compat_sigevent() populated the top part of si_ptr > with si_int.
Thanks, that makes sense. I was missing the fact that the conversion issue was actually around the in-kernel 64-bit version of the structure. Using si_int consistently does seem like it should do the right thing; I'll post a patch for tilegx32 big-endian to do the right thing here.
-- Chris Metcalf, EZChip Semiconductor http://www.ezchip.com
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