proc_int_k2u_conv_kop() reports the sign through *negp and the magnitude through *u_ptr, but for a negative value it hands the sign-extended int to the converter and negates the result: *u_ptr = k_ptr_op ? -k_ptr_op((ulong)val) : -(ulong)val; With div_hz() and CONFIG_HZ=1000 a stored -1000 becomes (ulong)-1000 / 1000 == 18446744073709550, and negating that wraps: # echo -1 > /proc/sys/net/ipv4/tcp_fin_timeout # cat /proc/sys/net/ipv4/tcp_fin_timeout -18428297329635842066 The magnitude is HZ dependent but the wrap is not: the negation happens after the division at every CONFIG_HZ. Take the magnitude first and convert that, which is what the open-coded version did before commit 2dc164a48e6f ("sysctl: Create converter functions with two new macros") folded it into a macro. The k_ptr_op == NULL branch was already correct. All three int converters that pass a k_ptr_op are affected: proc_dointvec_jiffies(), proc_dointvec_userhz_jiffies() and proc_dointvec_ms_jiffies(). Fixes: 2dc164a48e6f ("sysctl: Create converter functions with two new macros") Cc: stable@vger.kernel.org Reviewed-by: Bradley Morgan Signed-off-by: Zhan Xusheng --- kernel/sysctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index f7b75985d542..38597f26b34c 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -483,7 +483,7 @@ int proc_int_k2u_conv_kop(ulong *u_ptr, const int *k_ptr, bool *negp, if (val < 0) { *negp = true; - *u_ptr = k_ptr_op ? -k_ptr_op((ulong)val) : -(ulong)val; + *u_ptr = k_ptr_op ? k_ptr_op(-(ulong)val) : -(ulong)val; } else { *negp = false; *u_ptr = k_ptr_op ? k_ptr_op((ulong)val) : (ulong) val; -- 2.43.0