Messages in this thread | | | Date | Thu, 31 Mar 2022 08:17:30 +0200 | From | Thorsten Leemhuis <> | Subject | Bug 215734 - shared object loaded very low in memory ARM 32bit with kernel 5.17.0 |
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Hi, this is your Linux kernel regression tracker.
I noticed a regression report in bugzilla.kernel.org that afaics nobody acted upon since it was reported about a week ago, that's why I decided to forward it to the lists and all people that seemed to be relevant here. Note, this is the second regression report referencin a commit from H.J. Lu as culprit (9630f0d60fec ("fs/binfmt_elf: use PT_LOAD p_align values for static PIE")). I forwarded the first one on Monday already, but seems nothing happened: https://lore.kernel.org/all/cb5b81bd-9882-e5dc-cd22-54bdbaaefbbc@leemhuis.info/
Anyway, to get back to the latest report. To quote from https://bugzilla.kernel.org/show_bug.cgi?id=215734 :
> Jan Palus 2022-03-24 10:17:02 UTC > > This is a followup to https://sourceware.org/bugzilla/show_bug.cgi?id=28990 where ld.so --verify segfault was reported on binaries > 4MB. > > It appears that starting with kernel 5.17.0 shared object is loaded in the begging of address space at least on 32-bit ARM: > > /proc/<pid>/maps just before mmap (5.17): > 00400000-00429000 r-xp 00000000 b3:02 393320 /lib/ld-linux-armhf.so.3 > 00439000-0043c000 rw-p 00029000 b3:02 393320 /lib/ld-linux-armhf.so.3 > 76ffd000-76ffe000 r-xp 00000000 00:00 0 [sigpage] > 76ffe000-76fff000 r--p 00000000 00:00 0 [vvar] > 76fff000-77000000 r-xp 00000000 00:00 0 [vdso] > 7efdf000-7f000000 rw-p 00000000 00:00 0 [stack] > ffff0000-ffff1000 r-xp 00000000 00:00 0 [vectors] > > causing segfaults when mmaping large binaries at fixed address 0x10000 (ie done by ld.so --verify used by ldd). > > By comparison it is not the case for kernel 5.16.8: > > /proc/<pid>/maps just before mmap (5.16): > 76fc4000-76fed000 r-xp 00000000 b3:02 393320 /lib/ld-linux-armhf.so.3 > 76ffa000-76ffb000 r-xp 00000000 00:00 0 [sigpage] > 76ffb000-76ffc000 r--p 00000000 00:00 0 [vvar] > 76ffc000-76ffd000 r-xp 00000000 00:00 0 [vdso] > 76ffd000-77000000 rw-p 00029000 b3:02 393320 /lib/ld-linux-armhf.so.3 > 7efdf000-7f000000 rw-p 00000000 00:00 0 [stack] > ffff0000-ffff1000 r-xp 00000000 00:00 0 [vectors] > > [reply] [−] Comment 1 Jan Palus 2022-03-29 22:14:12 UTC > > First bad commit appears to be: > > From: "H.J. Lu" <hjl.tools@gmail.com> > Date: Wed, 19 Jan 2022 18:09:40 -0800 > Subject: fs/binfmt_elf: use PT_LOAD p_align values for static PIE > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9630f0d60fec5fbcaa4435a66f75df1dc9704b66 >
Could somebody take a look into this? Or was this discussed somewhere else already? Or even fixed?
Anyway, to get this tracked:
#regzbot introduced: 9630f0d60fec5fbcaa4435a66f75df1dc9704b6 #regzbot from: Jan Palus <jpalus@fastmail.com> #regzbot title: shared object loaded very low in memory ARM 32bit causing segfaults on binaries > 4MB #regzbot link: https://bugzilla.kernel.org/show_bug.cgi?id=215734
Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
P.S.: As the Linux kernel's regression tracker I'm getting a lot of reports on my table. I can only look briefly into most of them and lack knowledge about most of the areas they concern. I thus unfortunately will sometimes get things wrong or miss something important. I hope that's not the case here; if you think it is, don't hesitate to tell me in a public reply, it's in everyone's interest to set the public record straight.
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