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-rw-r--r--drivers/firmware/arm_sdei.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index b12b99a19f66..e7e36aab2386 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c
@@ -1128,6 +1128,14 @@ int sdei_event_handler(struct pt_regs *regs,
mm_segment_t orig_addr_limit;
u32 event_num = arg->event_num;
+ /*
+ * Save restore 'fs'.
+ * The architecture's entry code save/restores 'fs' when taking an
+ * exception from the kernel. This ensures addr_limit isn't inherited
+ * if you interrupted something that allowed the uaccess routines to
+ * access kernel memory.
+ * Do the same here because this doesn't come via the same entry code.
+ */
orig_addr_limit = get_fs();
set_fs(USER_DS);