Messages in this thread |  | | Date | Mon, 15 May 2023 17:57:09 +0900 | | Subject | Re: [PATCH v2] mm/mmap: Regression fix for unmapped_area{_topdown} | | From | Juhyung Park <> |
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Hi Liam,
It's a bit hard to follow this particular issue on v6.1 as there are many email threads related to this.
I just wanted to ask if whether this is fixed on mainline and v6.1 stable yet.
If there's a new thread tackling this issue, I'd appreciate it if you can link it here.
Thanks, regards
On 5/2/23 23:09, Liam R. Howlett wrote: > ...Adding Rick to the Cc this time. > > * Liam R. Howlett <Liam.Howlett@Oracle.com> [230502 10:08]: >> * Michael Keyes <mgkeyes@vigovproductions.net> [230430 18:41]: >>> On 29.04.23 15:32, Tad wrote: >>>> This reintroduces the issue described in >>>> https://lore.kernel.org/linux-mm/cb8dc31a-fef2-1d09-f133-e9f7b9f9e77a@sony.com/ >>> Yes, I also ran into this (even though I'd somehow missed it the >>> previous time). >> >> Rick Edgecombe reported something similar [1]. >> >> This is probably to do with my stack guard checks I recently added. >> >>> >>> Apparently the issue arises at mm/mmap.c:1582, where low_limit is set to >>> vm_end_gap(tmp). Occasionally, this returns a 64-bit address (e.g. >>> 0x7fedea581000), which is obviously greater than high_limit for a 32-bit >>> mmap, and causes the next call to mas_empty_area() to fail. >>> >>> I'm not sure why vm_end_gap(tmp) occasionally returns a 64-bit address, >>> or if the best solution is to just check for this and skip the retry if >>> it occurs… >>> >> >> Thanks for the debugging. I will look into it. >> >> I am currently trying to revise how the iterators, prev/next deal with >> shifting outside the requested limits. I suspect it's something to do >> with hitting the limit and what someone would assume the next operation >> means. >> >> [1] https://lore.kernel.org/linux-mm/32f156ba80010fd97dbaf0a0cdfc84366608624d.camel@intel.com/ > >
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