Re: [PATCH] linux-user: Fix AT_PHDR when program headers are relocated into their own segment

["valium" <valium7171@gmail.com>]

On Wed Jun 17, 2026 at 10:18 PM IST, Helge Deller wrote:
> It's sufficient if you let us know what it should be.

My real name is Akshit Yadav.
>> 
>>>> ---
>>>>    linux-user/elfload.c | 21 ++++++++++++++++++++-
>>>>    linux-user/qemu.h    |  1 +
>>>>    2 files changed, 21 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
>>>> index b05b8b0..8049c8a 100644
>>>> --- a/linux-user/elfload.c
>>>> +++ b/linux-user/elfload.c
>>>> @@ -699,7 +699,7 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
>>>>        /* There must be exactly DLINFO_ITEMS entries here, or the assert
>>>>         * on info->auxv_len will trigger.
>>>>         */
>>>> -    NEW_AUX_ENT(AT_PHDR, (abi_ulong)(info->load_addr + exec->e_phoff));
>>>> +    NEW_AUX_ENT(AT_PHDR, (abi_ulong)(info->phdr_addr));
>>>>        NEW_AUX_ENT(AT_PHENT, (abi_ulong)(sizeof (struct elf_phdr)));
>>>>        NEW_AUX_ENT(AT_PHNUM, (abi_ulong)(exec->e_phnum));
>>>>        NEW_AUX_ENT(AT_PAGESZ, (abi_ulong)(TARGET_PAGE_SIZE));
>>>> @@ -1469,6 +1469,12 @@ static void load_elf_image(const char *image_name, const ImageSource *src,
>>>>        info->data_offset = load_bias;
>>>>        info->load_addr = load_addr;
>>>>        info->entry = ehdr->e_entry + load_bias;
>>>> +    /*
>>>> +     * Fallback for AT_PHDR if the program headers do not fall within
>>>> +     * any PT_LOAD segment (see the loop below, which overrides this with
>>>> +     * the correct in-memory address when a containing segment is found).
>>>> +     */
>>>> +    info->phdr_addr = load_addr + ehdr->e_phoff;
>>>>        info->start_code = -1;
>>>>        info->end_code = 0;
>>>>        info->start_data = -1;
>>>> @@ -1523,6 +1529,19 @@ static void load_elf_image(const char *image_name, const ImageSource *src,
>>>>                vaddr_ef = vaddr + eppnt->p_filesz;
>>>>                vaddr_em = vaddr + eppnt->p_memsz;
>>>>    
>>>> +            /*
>>>> +             * If this segment contains the program headers, record their
>>>> +             * in-memory address for AT_PHDR. This matches the kernel, which
>>>> +             * locates the headers via the containing PT_LOAD rather than
>>>> +             * assuming load_addr + e_phoff (false when the phdrs are not
>>>> +             * mapped 1:1 from file offset 0, e.g. relocated into their own
>>>> +             * segment by a binary patcher).
>>>> +             */
>>>> +            if (eppnt->p_offset <= ehdr->e_phoff &&
>>>> +                ehdr->e_phoff < eppnt->p_offset + eppnt->p_filesz) {
>>>> +                info->phdr_addr = vaddr + (ehdr->e_phoff - eppnt->p_offset);
>>>> +            }
>>>> +
>>>>                /*
>>>>                 * Some segments may be completely empty, with a non-zero p_memsz
>>>>                 * but no backing file segment.
>>>> diff --git a/linux-user/qemu.h b/linux-user/qemu.h
>>>> index 07fe801..2268493 100644
>>>> --- a/linux-user/qemu.h
>>>> +++ b/linux-user/qemu.h
>>>> @@ -26,6 +26,7 @@
>>>>    struct image_info {
>>>>            abi_ulong       load_bias;
>>>>            abi_ulong       load_addr;
>>>> +        abi_ulong       phdr_addr;
>>>>            abi_ulong       start_code;
>>>>            abi_ulong       end_code;
>>>>            abi_ulong       start_data;
>> 
>>