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@xxxxxxxxxx> [230502 10:08]:
* Michael Keyes <mgkeyes@xxxxxxxxxxxxxxxxxxxx> [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@xxxxxxxx/
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@xxxxxxxxx/
