On Wed, Jun 19, 2024 at 01:34:11AM +0000, Liao Chang wrote: > When the new uretprobe system call was added [1], the xol slots reserved > for the uretprobe trampoline might be insufficient on some architecture. hum, uretprobe syscall is x86_64 specific, nothing was changed wrt slots or other architectures.. could you be more specific in what's changed? thanks, jirka > For example, on arm64, the trampoline is consist of three instructions > at least. So it should mark enough bits in area->bitmaps and > and area->slot_count for the reserved slots. > > [1] https://lore.kernel.org/all/20240611112158.40795-4-jolsa@xxxxxxxxxx/ > > Signed-off-by: Liao Chang <liaochang1@xxxxxxxxxx> > --- > kernel/events/uprobes.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index 2816e65729ac..efd2d7f56622 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -1485,7 +1485,7 @@ void * __weak arch_uprobe_trampoline(unsigned long *psize) > static struct xol_area *__create_xol_area(unsigned long vaddr) > { > struct mm_struct *mm = current->mm; > - unsigned long insns_size; > + unsigned long insns_size, slot_nr; > struct xol_area *area; > void *insns; > > @@ -1508,10 +1508,13 @@ static struct xol_area *__create_xol_area(unsigned long vaddr) > > area->vaddr = vaddr; > init_waitqueue_head(&area->wq); > - /* Reserve the 1st slot for get_trampoline_vaddr() */ > - set_bit(0, area->bitmap); > - atomic_set(&area->slot_count, 1); > insns = arch_uprobe_trampoline(&insns_size); > + /* Reserve enough slots for the uretprobe trampoline */ > + for (slot_nr = 0; > + slot_nr < max((insns_size / UPROBE_XOL_SLOT_BYTES), 1); > + slot_nr++) > + set_bit(slot_nr, area->bitmap); > + atomic_set(&area->slot_count, slot_nr); > arch_uprobe_copy_ixol(area->pages[0], 0, insns, insns_size); > > if (!xol_add_vma(mm, area)) > -- > 2.34.1 >
