Hi Al Viro, On Mon, 15 Feb 2021 at 01:25, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > On Mon, Jan 25, 2021 at 10:01:48PM +0530, Naresh Kamboju wrote: > > commit 8a3cc755b13808eba74846dfd1033fcbc21f9a65 > > Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > > Date: Sun Mar 8 09:16:37 2020 -0400 > > > > coredump: don't bother with do_truncate() > > > > have dump_skip() just remember how much needs to be skipped, > > leave actual seeks/writing zeroes to the next dump_emit() > > or the end of coredump output, whichever comes first. > > And instead of playing with do_truncate() in the end, just > > write one NUL at the end of the last gap (if any). > > > > Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > > > > fs/binfmt_elf.c | 1 - > > fs/coredump.c | 56 +++++++++++++++++++++++++++--------------------- > > include/linux/binfmts.h | 1 + > > include/linux/coredump.h | 1 - > > > > > > Test case output link, > > https://lkft.validation.linaro.org/scheduler/job/2184975#L1369 > > https://lkft.validation.linaro.org/scheduler/job/2184972#L1358 > > I think I see what's going on. Could you check if the following > fixes your reproducer? > > diff --git a/arch/powerpc/platforms/cell/spufs/coredump.c b/arch/powerpc/platforms/cell/spufs/coredump.c > index 60b5583e9eaf..1a587618015c 100644 > --- a/arch/powerpc/platforms/cell/spufs/coredump.c > +++ b/arch/powerpc/platforms/cell/spufs/coredump.c > @@ -149,8 +149,7 @@ static int spufs_arch_write_note(struct spu_context *ctx, int i, > return -EIO; > } > > - if (!dump_skip(cprm, roundup(cprm->pos - ret + sz, 4) - cprm->pos)) > - return -EIO; > + dump_skip_to(cprm, roundup(cprm->pos - ret + sz, 4)); > return 0; > } > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > index 66137d5dca5f..474a3c7dd5ce 100644 > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -2267,8 +2267,7 @@ static int elf_core_dump(struct coredump_params *cprm) > goto end_coredump; > > /* Align to page */ > - if (!dump_skip(cprm, dataoff - cprm->pos)) > - goto end_coredump; > + dump_skip_to(cprm, dataoff); > > for (i = 0; i < vma_count; i++) { > struct core_vma_metadata *meta = vma_meta + i; > diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c > index be4062b8ba75..01f043971644 100644 > --- a/fs/binfmt_elf_fdpic.c > +++ b/fs/binfmt_elf_fdpic.c > @@ -1640,8 +1640,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm) > goto end_coredump; > } > > - if (!dump_skip(cprm, dataoff - cprm->pos)) > - goto end_coredump; > + dump_skip_to(cprm, dataoff); > > if (!elf_fdpic_dump_segments(cprm, vma_meta, vma_count)) > goto end_coredump; > diff --git a/fs/coredump.c b/fs/coredump.c > index 27a93f724251..bfac7422cd14 100644 > --- a/fs/coredump.c > +++ b/fs/coredump.c > @@ -894,7 +894,14 @@ int dump_emit(struct coredump_params *cprm, const void *addr, int nr) > } > EXPORT_SYMBOL(dump_emit); > > -int dump_skip(struct coredump_params *cprm, size_t nr) > +void dump_skip_to(struct coredump_params *cprm, unsigned long pos) > +{ > + cprm->to_skip = pos - cprm->pos; > + return 0; fs/coredump.c:903:9: error: 'return' with a value, in function returning void [-Werror=return-type] 903 | return 0; | ^ Build failed due to above error. build log link, https://gitlab.com/Linaro/lkft/users/naresh.kamboju/linux/-/jobs/1029838856#L383 - Naresh
