6.12-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit 1898300abf3508bca152e65b36cce5bf93d7e63e ]
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: Sasha Levin sashal@kernel.org --- arch/riscv/include/asm/cmpxchg.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h index ebbce134917cc..6efa95ad033ab 100644 --- a/arch/riscv/include/asm/cmpxchg.h +++ b/arch/riscv/include/asm/cmpxchg.h @@ -169,7 +169,7 @@ break; \ case 4: \ __arch_cmpxchg(".w", ".w" sc_sfx, prepend, append, \ - __ret, __ptr, (long), __old, __new); \ + __ret, __ptr, (long)(int)(long), __old, __new); \ break; \ case 8: \ __arch_cmpxchg(".d", ".d" sc_sfx, prepend, append, \