On Fri, Oct 14, 2016 at 1:25 PM, Will Deacon <[email protected]> wrote: > On Fri, Oct 14, 2016 at 12:53:56PM +0200, Dmitry Vyukov wrote: >> KASAN stack instrumentation poisons stack redzones on function entry >> and unpoisons them on function exit. If a function exits abnormally >> (e.g. with a longjmp like jprobe_return()), stack redzones are left >> poisoned. Later this leads to random KASAN false reports. >> >> Unpoison stack redzones in the frames we are going to jump over >> before doing actual longjmp in jprobe_return(). >> >> Signed-off-by: Dmitry Vyukov <[email protected]> >> Cc: Mark Rutland <[email protected]> >> Cc: Catalin Marinas <[email protected]> >> Cc: Andrey Ryabinin <[email protected]> >> Cc: Lorenzo Pieralisi <[email protected]> >> Cc: Alexander Potapenko <[email protected]> >> Cc: Will Deacon <[email protected]> >> Cc: Ingo Molnar <[email protected]> >> Cc: Andrew Morton <[email protected]> >> Cc: Thomas Gleixner <[email protected]> >> Cc: "H. Peter Anvin" <[email protected]> >> Cc: Ananth N Mavinakayanahalli <[email protected]> >> Cc: Anil S Keshavamurthy <[email protected]> >> Cc: "David S. Miller" <[email protected]> >> Cc: Masami Hiramatsu <[email protected]> >> Cc: [email protected] >> Cc: [email protected] >> >> -- >> >> Changes since v1: >> - leave kasan_unpoison_remaining_stack() intact >> - instead add kasan_unpoison_stack_above_sp_to() >> - rename kasan_unpoison_remaining_stack() to >> kasan_unpoison_task_stack_below() >> >> Changes since v2: >> - fix build by adding return type to kasan_unpoison_stack_above_sp_to >> (tested v2 with it, but forgot to git add) > > I get build warnings with this patch applied and KASAN enabled: > > mm/kasan/kasan.c: In function ‘kasan_unpoison_task_stack_below’: > mm/kasan/kasan.c:82:34: warning: passing argument 2 of > ‘__kasan_unpoison_stack’ discards ‘const’ qualifier from pointer target type > [-Wdiscarded-qualifiers] > __kasan_unpoison_stack(current, watermark); > ^~~~~~~~~ > mm/kasan/kasan.c:65:13: note: expected ‘void *’ but argument is of type > ‘const void *’ > static void __kasan_unpoison_stack(struct task_struct *task, void *sp) > ^~~~~~~~~~~~~~~~~~~~~~ > mm/kasan/kasan.c: In function ‘kasan_unpoison_stack_above_sp_to’: > mm/kasan/kasan.c:92:27: error: called object ‘current_stack_pointer’ is not a > function or function pointer > const void *sp = (void *)current_stack_pointer(); > ^~~~~~~~~~~~~~~~~~~~~
Mailed v4. Thanks
