6.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andreas Schwab <schwab@xxxxxxx>
commit 1898300abf3508bca152e65b36cce5bf93d7e63e upstream.
Sign extend also an unsigned compare value to match what lr.w is doing.
Otherwise try_cmpxchg may spuriously return true when used on a u32 value
that has the sign bit set, as it happens often in inode_set_ctime_current.
Do this in three conversion steps. The first conversion to long is needed
to avoid a -Wpointer-to-int-cast warning when arch_cmpxchg is used with a
pointer type. Then convert to int and back to long to always sign extend
the 32-bit value to 64-bit.
Fixes: 6c58f25e6938 ("riscv/atomic: Fix sign extension for RV64I")
Signed-off-by: Andreas Schwab <schwab@xxxxxxx>
Reviewed-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
Tested-by: Xi Ruoyao <xry111@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/mvmed0k4prh.fsf@xxxxxxx
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/riscv/include/asm/cmpxchg.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/riscv/include/asm/cmpxchg.h
+++ b/arch/riscv/include/asm/cmpxchg.h
@@ -231,7 +231,7 @@
__arch_cmpxchg(".w", ".w" sc_sfx, ".w" cas_sfx, \
sc_prepend, sc_append, \
cas_prepend, cas_append, \
- __ret, __ptr, (long), __old, __new); \
+ __ret, __ptr, (long)(int)(long), __old, __new); \
break; \
case 8: \
__arch_cmpxchg(".d", ".d" sc_sfx, ".d" cas_sfx, \
