riscv/mm: Add handling for VM_FAULT_SIGSEGV in mm_fault_error()

Handle VM_FAULT_SIGSEGV in the page fault path so that we correctly
kill the process and we don't BUG() the kernel.

Fixes: 07037db5d479 ("RISC-V: Paging and MMU")
Signed-off-by: Zhe Qiao <qiaozhe@iscas.ac.cn>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240731084547.85380-1-qiaozhe@iscas.ac.cn
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 5224f373380225a2dfdecd40bfc01ce8f5d13bc0..a9f2b4af8f3f18442117f79855cfe89b39ce4d7e 100644 (file)
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -61,26 +61,27 @@ static inline void no_context(struct pt_regs *regs, unsigned long addr)
 
 static inline void mm_fault_error(struct pt_regs *regs, unsigned long addr, vm_fault_t fault)
 {
+       if (!user_mode(regs)) {
+               no_context(regs, addr);
+               return;
+       }
+
        if (fault & VM_FAULT_OOM) {
                /*
                 * We ran out of memory, call the OOM killer, and return the userspace
                 * (which will retry the fault, or kill us if we got oom-killed).
                 */
-               if (!user_mode(regs)) {
-                       no_context(regs, addr);
-                       return;
-               }
                pagefault_out_of_memory();
                return;
        } else if (fault & (VM_FAULT_SIGBUS | VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) {
                /* Kernel mode? Handle exceptions or die */
-               if (!user_mode(regs)) {
-                       no_context(regs, addr);
-                       return;
-               }
                do_trap(regs, SIGBUS, BUS_ADRERR, addr);
                return;
+       } else if (fault & VM_FAULT_SIGSEGV) {
+               do_trap(regs, SIGSEGV, SEGV_MAPERR, addr);
+               return;
        }
+
        BUG();
 }