[PATCH 6.6 091/121] riscv/mm: Add handling for VM_FAULT_SIGSEGV in mm_fault_error()

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6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Zhe Qiao <qiaozhe@xxxxxxxxxxx>

[ 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>
---
 arch/riscv/mm/fault.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

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();
 }
 
-- 
2.43.0







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