Messages in this thread | | | Date | Thu, 10 Mar 2022 21:17:58 +0000 | Subject | Re: [PATCH v3 00/23] Add generic vdso_base tracking | From | Dmitry Safonov <> |
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Hi Christophe,
On 3/9/22 15:41, Christophe Leroy wrote: > Hi Dmitry, > > I'm wondering the status of this series.
Yeah, I plan to work on v4 addressing the reviews. WFH has quite affected my work on side-projects and I've laid aside for a while this patch set that touches every architecture and is besides a bit challenging to upstream.
> 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/
Please, go ahead with that - I'll base v4 patches on the top of that. Thanks for pinging me about this.
> 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 >
Thanks, Dmitry
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