Messages in this thread | | | Date | Tue, 07 May 2019 16:48:03 -0700 (PDT) | Subject | Re: [PATCH] riscv: fix locking violation in page fault handler | From | Palmer Dabbelt <> |
| |
On Tue, 07 May 2019 00:36:46 PDT (-0700), schwab@suse.de wrote: > When a user mode process accesses an address in the vmalloc area > do_page_fault tries to unlock the mmap semaphore when it isn't locked. > > Signed-off-by: Andreas Schwab <schwab@suse.de> > --- > arch/riscv/mm/fault.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c > index 88401d5125bc..c51878e5a66a 100644 > --- a/arch/riscv/mm/fault.c > +++ b/arch/riscv/mm/fault.c > @@ -181,6 +181,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs) > up_read(&mm->mmap_sem); > /* User mode accesses just cause a SIGSEGV */ > if (user_mode(regs)) { > +bad_area_do_trap: > do_trap(regs, SIGSEGV, code, addr, tsk); > return; > } > @@ -230,7 +231,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs) > int index; > > if (user_mode(regs)) > - goto bad_area; > + goto bad_area_do_trap; > > /* > * Synchronize this task's top level page-table
I got lost with all the gotos, I think something like this is cleaner
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index 26293bc053a8..cec8be9e2d6a 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -229,8 +229,9 @@ asmlinkage void do_page_fault(struct pt_regs *regs) pte_t *pte_k; int index;
+ /* User mode accesses just cause a SIGSEGV */ if (user_mode(regs)) - goto bad_area; + return do_trap(regs, SIGSEGV, code, addr, tsk); /* * Synchronize this task's top level page-table
Unless anyone has a better idea?
Either way:
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
LMK if you, or anyone else, has a preference. I'm assuming this will go in through my tree, so I've picked up my version for now :)
| |