From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
Guenter reported a lockdep splat that appears to have been present for a
while in v6.1.y & the backports of the riscv_patch_in_stop_machine dance
did nothing to help here, as the lock is not being taken when
patch_text_nosync() is called in riscv_cpufeature_patch_func().
Add the lock/unlock; elide the splat.
Fixes: c15ac4fd60d5 ("riscv/ftrace: Add dynamic function tracer support")
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
---
arch/riscv/kernel/cpufeature.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 694267d1fe81..fd1238df6149 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -9,6 +9,7 @@
#include <linux/bitmap.h>
#include <linux/ctype.h>
#include <linux/libfdt.h>
+#include <linux/memory.h>
#include <linux/module.h>
#include <linux/of.h>
#include <asm/alternative.h>
@@ -316,8 +317,11 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
}
tmp = (1U << alt->errata_id);
- if (cpu_req_feature & tmp)
+ if (cpu_req_feature & tmp) {
+ mutex_lock(&text_mutex);
patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
+ mutex_unlock(&text_mutex);
+ }
}
}
#endif
--
2.39.2
