Denys, let's not discuss this offlist... add lkml/cc's On 09/11, Denys Vlasenko wrote: > > If elf_note_info_init fails to allocate memory for info->fields, > it frees already alloceted stuff and returns error to its caller, > fill_note_info. Which in turn returns error to its caller, > elf_core_dump. Which jumps to cleanup label and calls free_note_info, > which will happily try to free all info->fields again. BOOM.
This is !CORE_DUMP_USE_REGSET case, please mention this in the changelog. And s/fs:/coredump:/ in the subject ;) OK, I think you are right, but unless I missed something there is a better fix. > This is the fix. > > Signed-off-by: Denys Vlasenko <[email protected]> > --- > fs/binfmt_elf.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > index 760d7f5..b2b7034 100644 > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -1617,7 +1617,7 @@ static void free_note_info(struct elf_note_info *info) > kfree(info->psinfo.data); > } > > -#else > +#else /* !CORE_DUMP_USE_REGSET */ > > /* Here is the structure in which status of each thread is captured. */ > struct elf_thread_status > @@ -1718,6 +1718,8 @@ static int elf_note_info_init(struct elf_note_info > *info) > kfree(info->psinfo); > notes_free: > kfree(info->notes); > + /* The caller will try to clean us up again, must set ptrs to NULL */ Exactly. The caller will do free_note_info() and info was zeroed at the start. See below > + memset(info, 0, sizeof(*info)); Yes, this will fix the problem. But, again, the caller does free_note_info(), so why elf_note_info_init() tries to handle the kmalloc failures? Afaics, we can simplify the code and fix the bug. What do you think about the patch below? Oleg. --- x/fs/binfmt_elf.c +++ x/fs/binfmt_elf.c @@ -1696,30 +1696,19 @@ static int elf_note_info_init(struct elf return 0; info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL); if (!info->psinfo) - goto notes_free; + return 0; info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL); if (!info->prstatus) - goto psinfo_free; + return 0; info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL); if (!info->fpu) - goto prstatus_free; + return 0; #ifdef ELF_CORE_COPY_XFPREGS info->xfpu = kmalloc(sizeof(*info->xfpu), GFP_KERNEL); if (!info->xfpu) - goto fpu_free; + return 0; #endif return 1; -#ifdef ELF_CORE_COPY_XFPREGS - fpu_free: - kfree(info->fpu); -#endif - prstatus_free: - kfree(info->prstatus); - psinfo_free: - kfree(info->psinfo); - notes_free: - kfree(info->notes); - return 0; } static int fill_note_info(struct elfhdr *elf, int phdrs, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
