On Fri, Oct 14, 2016 at 1:25 PM, Will Deacon <will.dea...@arm.com> 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 <dvyu...@google.com> >> Cc: Mark Rutland <mark.rutl...@arm.com> >> Cc: Catalin Marinas <catalin.mari...@arm.com> >> Cc: Andrey Ryabinin <ryabinin....@gmail.com> >> Cc: Lorenzo Pieralisi <lorenzo.pieral...@arm.com> >> Cc: Alexander Potapenko <gli...@google.com> >> Cc: Will Deacon <will.dea...@arm.com> >> Cc: Ingo Molnar <mi...@kernel.org> >> Cc: Andrew Morton <a...@linux-foundation.org> >> Cc: Thomas Gleixner <t...@linutronix.de> >> Cc: "H. Peter Anvin" <h...@zytor.com> >> Cc: Ananth N Mavinakayanahalli <ana...@linux.vnet.ibm.com> >> Cc: Anil S Keshavamurthy <anil.s.keshavamur...@intel.com> >> Cc: "David S. Miller" <da...@davemloft.net> >> Cc: Masami Hiramatsu <mhira...@kernel.org> >> Cc: x...@kernel.org >> Cc: kasan-...@googlegroups.com >> >> -- >> >> 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
