Messages in this thread | | | Date | Wed, 9 Mar 2022 16:41:29 +0100 | Subject | Re: [PATCH v3 00/23] Add generic vdso_base tracking | From | Christophe Leroy <> |
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Hi Dmitry,
I'm wondering the status of this series.
Wondering what to do while reviewing pending powerpc patches and especially https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20201103171336.98883-1-ldufour@linux.ibm.com/
Christophe
Le 11/06/2021 à 20:02, Dmitry Safonov a écrit : > v3 Changes: > - Migrated arch/powerpc to vdso_base > - Added x86/selftest for unmapped vdso & no landing on fast syscall > - Review comments from Andy & Christophe (thanks!) > - Amended s/born process/execed process/ everywhere I noticed > - Build robot warning on cast from __user pointer > > I've tested it on x86, I would appreciate any help with > Tested-by on arm/arm64/mips/powerpc/s390/... platforms. > > One thing I've noticed while cooking this and haven't found a clean > way to solve is zero-terminated .pages[] array in vdso mappings, which > is not always zero-terminated but works by the reason of > VM_DONTEXPAND on mappings. > > v2 Changes: > - Rename user_landing to vdso_base as it tracks vDSO VMA start address, > rather than the explicit address to land (Andy) > - Reword and don't use "new-execed" and "new-born" task (Andy) > - Fix failures reported by build robot > > Started from discussion [1], where was noted that currently a couple of > architectures support mremap() for vdso/sigpage, but not munmap(). > If an application maps something on the ex-place of vdso/sigpage, > later after processing signal it will land there (good luck!) > > Patches set is based on linux-next (next-20201123) and it depends on > changes in x86/cleanups (those reclaim TIF_IA32/TIF_X32) and also > on my changes in akpm (fixing several mremap() issues). > > Logically, the patches set divides on: > - patch 1: a cleanup for patches in x86/cleanups > - patches 2-13: cleanups for arch_setup_additional_pages() > - patches 13-14: x86 signal changes for unmapped vdso > - patches 15-22: provide generic vdso_base in mm_struct > - patch 23: selftest for unmapped vDSO & fast syscalls > > In the end, besides cleanups, it's now more predictable what happens for > applications with unmapped vdso on architectures those support .mremap() > for vdso/sigpage. > > I'm aware of only one user that unmaps vdso - Valgrind [2]. > (there possibly are more, but this one is "special", it unmaps vdso, but > not vvar, which confuses CRIU [Checkpoint Restore In Userspace], that's > why I'm aware of it) >
I'm wondering the status of this series.
Wondering what to do while reviewing pending powerpc patches and especially https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20201103171336.98883-1-ldufour@linux.ibm.com/
Christophe
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