diff options
| -rw-r--r-- | arch/powerpc/mm/fault.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 76d8e7cc7805..2dd69bf4af46 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -206,7 +206,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, int trap = TRAP(regs); int is_exec = trap == 0x400; int fault; - int rc = 0; + int rc = 0, store_update_sp = 0; #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) /* @@ -280,6 +280,14 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); + /* + * We want to do this outside mmap_sem, because reading code around nip + * can result in fault, which will cause a deadlock when called with + * mmap_sem held + */ + if (user_mode(regs)) + store_update_sp = store_updates_sp(regs); + /* When running in the kernel we expect faults to occur only to * addresses in user space. All other faults represent errors in the * kernel and should generate an OOPS. Unfortunately, in the case of an @@ -345,8 +353,7 @@ retry: * between the last mapped region and the stack will * expand the stack rather than segfaulting. */ - if (address + 2048 < uregs->gpr[1] - && (!user_mode(regs) || !store_updates_sp(regs))) + if (address + 2048 < uregs->gpr[1] && !store_update_sp) goto bad_area; } if (expand_stack(vma, address)) |