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coredump: refactor page range dumping into common helper

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Both fs/binfmt_elf.c and fs/binfmt_elf_fdpic.c need to dump ranges of
pages into the coredump file.  Extract that logic into a common helper.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200827114932.3572699-4-jannh@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jann Horn
2020-10-15 20:12:46 -07:00
committed by Linus Torvalds
parent df0c09c011
commit afc63a97b7
4 changed files with 41 additions and 35 deletions
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34
fs/coredump.c
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@@ -876,6 +876,40 @@ int dump_skip(struct coredump_params *cprm, size_t nr)
}
EXPORT_SYMBOL(dump_skip);
#ifdef CONFIG_ELF_CORE
int dump_user_range(struct coredump_params *cprm, unsigned long start,
unsigned long len)
{
unsigned long addr;
for (addr = start; addr < start + len; addr += PAGE_SIZE) {
struct page *page;
int stop;
/*
* To avoid having to allocate page tables for virtual address
* ranges that have never been used yet, and also to make it
* easy to generate sparse core files, use a helper that returns
* NULL when encountering an empty page table entry that would
* otherwise have been filled with the zero page.
*/
page = get_dump_page(addr);
if (page) {
void *kaddr = kmap(page);
stop = !dump_emit(cprm, kaddr, PAGE_SIZE);
kunmap(page);
put_page(page);
} else {
stop = !dump_skip(cprm, PAGE_SIZE);
}
if (stop)
return 0;
}
return 1;
}
#endif
int dump_align(struct coredump_params *cprm, int align)
{
unsigned mod = cprm->pos & (align - 1);