6.13-stable review patch. If anyone has any objections, please let me know.
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From: Andreas Schwab schwab@suse.de
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@suse.de Reviewed-by: Alexandre Ghiti alexghiti@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com Tested-by: Xi Ruoyao xry111@xry111.site Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/mvmed0k4prh.fsf@suse.de Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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, \