Tools like readelf/llvm-readelf use p_align to parse a PT_NOTE program header as an array of 4-byte entries or 8-byte entries. Currently, there are workarounds[1] in place for Linux to treat p_align==0 as 4. However, it would be more appropriate to set the correct alignment so that tools do not have to rely on guesswork. FreeBSD coredumps set p_align to 4 as well. [1]: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=82ed9683ec099d8205dc499ac84febc975235af6 [2]: https://reviews.llvm.org/D150022 --- fs/binfmt_elf.c | 2 +- fs/binfmt_elf_fdpic.c | 2 +- fs/proc/vmcore.c | 4 ++-- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 1033fbdfdbec..44b4c42ab8e8 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1517,7 +1517,7 @@ static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset) phdr->p_filesz = sz; phdr->p_memsz = 0; phdr->p_flags = 0; - phdr->p_align = 0; + phdr->p_align = 4; } static void fill_note(struct memelfnote *note, const char *name, int type, diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index 05a1471d5283..d76ad3d4f676 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1269,7 +1269,7 @@ static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offs phdr->p_filesz = sz; phdr->p_memsz = 0; phdr->p_flags = 0; - phdr->p_align = 0; + phdr->p_align = 4; return; } diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 03f5963914a1..cb80a7703d58 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -877,7 +877,7 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz, phdr.p_offset = roundup(note_off, PAGE_SIZE); phdr.p_vaddr = phdr.p_paddr = 0; phdr.p_filesz = phdr.p_memsz = phdr_sz; - phdr.p_align = 0; + phdr.p_align = 4; /* Add merged PT_NOTE program header*/ tmp = elfptr + sizeof(Elf64_Ehdr); @@ -1068,7 +1068,7 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz, phdr.p_offset = roundup(note_off, PAGE_SIZE); phdr.p_vaddr = phdr.p_paddr = 0; phdr.p_filesz = phdr.p_memsz = phdr_sz; - phdr.p_align = 0; + phdr.p_align = 4; /* Add merged PT_NOTE program header*/ tmp = elfptr + sizeof(Elf32_Ehdr); -- 2.40.1.606.ga4b1b128d6-goog
