uffd: Fix page fault address

[yota9]

The page_size() returns unsigned int value that is after "bitwise not"
is promoted to unsigned long (msg->arg.pagefault.address) value. Sinc
e the value is unsigned promotion is done with 0 MSB that results in
lost of MSB pagefault address bits. Cast page_size to unsigned long
first to avoid such situation.

[adrianreber]

@rppt PTAL

[codecov-commenter]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (5e37ccf) 70.43% compared to head (75a7da0) 70.53%.

❗ Current head 75a7da0 differs from pull request most recent head 5a31b86. Consider uploading reports for the commit 5a31b86 to get more accurate results

Additional details and impacted files

@@             Coverage Diff              @@
##           criu-dev    #2270      +/-   ##
============================================
+ Coverage     70.43%   70.53%   +0.10%     
============================================
  Files           133      132       -1     
  Lines         33518    33507      -11     
============================================
+ Hits          23607    23634      +27     
+ Misses         9911     9873      -38     

Files	Coverage Δ
criu/uffd.c	78.41% <ø> (+5.84%)	⬆️

... and 6 files with indirect coverage changes

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[minhbq-99]

It's a nice catch. page_size in defined in criu/include/common/arch/*/asm/page.h. Interestingly, on x86, s390, arm, it returns unsigned long which does not cause the above issue. However, on aarch64, mips, ppc64, it returns unsigned int. I wonder if changing the page_size to return unsigned long in all archs is a good solution.

[rppt]

It's a nice catch. page_size in defined in criu/include/common/arch/*/asm/page.h. Interestingly, on x86, s390, arm, it returns unsigned long which does not cause the above issue. However, on aarch64, mips, ppc64, it returns unsigned int. I wonder if changing the page_size to return unsigned long in all archs is a good solution.

I think it is. Adding a cast in uffd.c is more of a band aid and making page_size() return unsigned long is the proper solution IMO.

[yota9]

It's a nice catch. page_size in defined in criu/include/common/arch/*/asm/page.h. Interestingly, on x86, s390, arm, it returns unsigned long which does not cause the above issue. However, on aarch64, mips, ppc64, it returns unsigned int. I wonder if changing the page_size to return unsigned long in all archs is a good solution.

Thanks for further investigations, I've made page_size() to return unsigned long in all the arches and couple of other places.

[rppt]

It's a nice catch. page_size in defined in criu/include/common/arch/*/asm/page.h. Interestingly, on x86, s390, arm, it returns unsigned long which does not cause the above issue. However, on aarch64, mips, ppc64, it returns unsigned int. I wonder if changing the page_size to return unsigned long in all archs is a good solution.

Thanks for further investigations, I've made page_size() to return unsigned long in all the arches and couple of other places.

It looks like you've missed loongarch64 :)

[yota9]

True, done. Thanks!

It's a nice catch. page_size in defined in criu/include/common/arch/*/asm/page.h. Interestingly, on x86, s390, arm, it returns unsigned long which does not cause the above issue. However, on aarch64, mips, ppc64, it returns unsigned int. I wonder if changing the page_size to return unsigned long in all archs is a good solution.

Thanks for further investigations, I've made page_size() to return unsigned long in all the arches and couple of other places.

It looks like you've missed loongarch64 :)

[yota9]

I'm not authorized to merge this pull request, so please do it for me, thanks!