Patch "riscv/mm: Add handling for VM_FAULT_SIGSEGV in mm_fault_error()" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     riscv-mm-add-handling-for-vm_fault_sigsegv-in-mm_fau.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit e8b5f652295e912b2b1a211bc42091e6a3fb2ba7
Author: Zhe Qiao <qiaozhe@xxxxxxxxxxx>
Date:   Wed Jul 31 16:45:47 2024 +0800

    riscv/mm: Add handling for VM_FAULT_SIGSEGV in mm_fault_error()
    
    [ Upstream commit 0c710050c47d45eb77b28c271cddefc5c785cb40 ]
    
    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@xxxxxxxxxxx>
    Reviewed-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240731084547.85380-1-qiaozhe@xxxxxxxxxxx
    Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 90d4ba36d1d06..655b2b1bb529f 100644
--- 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();
 }