[PATCH net-next] time: jiffies_delta_to_clock_t() helper to the rescue
From: Eric Dumazet <hidden>
Date: 2012-08-09 07:14:04
From: Eric Dumazet <edumazet@google.com> Various /proc/net files sometimes report crazy timer values, expressed in clock_t units. This happens when an expired timer delta (expires - jiffies) is passed to jiffies_to_clock_t(). This function has an overflow in : return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ); commit cbbc719fccdb8cb (time: Change jiffies_to_clock_t() argument type to unsigned long) only got around the problem. As we cant output negative values in /proc/net/tcp without breaking various tools, I suggest adding a jiffies_delta_to_clock_t() wrapper that caps the negative delta to a 0 value. Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Maciej Żenczykowski <redacted> Cc: Thomas Gleixner <redacted> Cc: Paul Gortmaker <redacted> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: hank <redacted> --- include/linux/jiffies.h | 6 ++++++ net/bridge/br_fdb.c | 2 +- net/bridge/br_stp_timer.c | 2 +- net/core/rtnetlink.c | 2 +- net/ipv4/igmp.c | 7 +++++-- net/ipv4/tcp_ipv4.c | 13 +++++-------- net/ipv6/tcp_ipv6.c | 9 +++------ 7 files changed, 22 insertions(+), 19 deletions(-)
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 265e2c3..aded9b1 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h@@ -303,7 +303,13 @@ extern void jiffies_to_timespec(const unsigned long jiffies, extern unsigned long timeval_to_jiffies(const struct timeval *value); extern void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value); + extern clock_t jiffies_to_clock_t(unsigned long x); +static inline clock_t jiffies_delta_to_clock_t(long delta) +{ + return jiffies_to_clock_t(max(0L, delta)); +} + extern unsigned long clock_t_to_jiffies(unsigned long x); extern u64 jiffies_64_to_clock_t(u64 x); extern u64 nsec_to_clock_t(u64 x);
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index d21f323..9ce430b 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c@@ -312,7 +312,7 @@ int br_fdb_fillbuf(struct net_bridge *br, void *buf, fe->is_local = f->is_local; if (!f->is_static) - fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->updated); + fe->ageing_timer_value = jiffies_delta_to_clock_t(jiffies - f->updated); ++fe; ++num; }
diff --git a/net/bridge/br_stp_timer.c b/net/bridge/br_stp_timer.c
index a6747e6..c3530a8 100644
--- a/net/bridge/br_stp_timer.c
+++ b/net/bridge/br_stp_timer.c@@ -170,5 +170,5 @@ void br_stp_port_timer_init(struct net_bridge_port *p) unsigned long br_timer_value(const struct timer_list *timer) { return timer_pending(timer) - ? jiffies_to_clock_t(timer->expires - jiffies) : 0; + ? jiffies_delta_to_clock_t(timer->expires - jiffies) : 0; }
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 2c5a0a0..db037c9 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c@@ -618,7 +618,7 @@ int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst, u32 id, long expires, u32 error) { struct rta_cacheinfo ci = { - .rta_lastuse = jiffies_to_clock_t(jiffies - dst->lastuse), + .rta_lastuse = jiffies_delta_to_clock_t(jiffies - dst->lastuse), .rta_used = dst->__use, .rta_clntref = atomic_read(&(dst->__refcnt)), .rta_error = error,
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 6699f23..0b5580c 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c@@ -2435,6 +2435,8 @@ static int igmp_mc_seq_show(struct seq_file *seq, void *v) struct ip_mc_list *im = (struct ip_mc_list *)v; struct igmp_mc_iter_state *state = igmp_mc_seq_private(seq); char *querier; + long delta; + #ifdef CONFIG_IP_MULTICAST querier = IGMP_V1_SEEN(state->in_dev) ? "V1" : IGMP_V2_SEEN(state->in_dev) ? "V2" :
@@ -2448,11 +2450,12 @@ static int igmp_mc_seq_show(struct seq_file *seq, void *v) state->dev->ifindex, state->dev->name, state->in_dev->mc_count, querier); } + delta = im->timer.expires - jiffies; seq_printf(seq, "\t\t\t\t%08X %5d %d:%08lX\t\t%d\n", im->multiaddr, im->users, - im->tm_running, im->tm_running ? - jiffies_to_clock_t(im->timer.expires-jiffies) : 0, + im->tm_running, + im->tm_running ? jiffies_delta_to_clock_t(delta) : 0, im->reporter); } return 0;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 42b2a6a..c660d2c 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c@@ -2385,7 +2385,7 @@ static void get_openreq4(const struct sock *sk, const struct request_sock *req, struct seq_file *f, int i, int uid, int *len) { const struct inet_request_sock *ireq = inet_rsk(req); - int ttd = req->expires - jiffies; + long delta = req->expires - jiffies; seq_printf(f, "%4d: %08X:%04X %08X:%04X" " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
@@ -2397,7 +2397,7 @@ static void get_openreq4(const struct sock *sk, const struct request_sock *req, TCP_SYN_RECV, 0, 0, /* could print option size, but that is af dependent. */ 1, /* timers active (only the expire timer) */ - jiffies_to_clock_t(ttd), + jiffies_delta_to_clock_t(delta), req->retrans, uid, 0, /* non standard timer */
@@ -2448,7 +2448,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len) tp->write_seq - tp->snd_una, rx_queue, timer_active, - jiffies_to_clock_t(timer_expires - jiffies), + jiffies_delta_to_clock_t(timer_expires - jiffies), icsk->icsk_retransmits, sock_i_uid(sk), icsk->icsk_probes_out,
@@ -2467,10 +2467,7 @@ static void get_timewait4_sock(const struct inet_timewait_sock *tw, { __be32 dest, src; __u16 destp, srcp; - int ttd = tw->tw_ttd - jiffies; - - if (ttd < 0) - ttd = 0; + long delta = tw->tw_ttd - jiffies; dest = tw->tw_daddr; src = tw->tw_rcv_saddr;
@@ -2480,7 +2477,7 @@ static void get_timewait4_sock(const struct inet_timewait_sock *tw, seq_printf(f, "%4d: %08X:%04X %08X:%04X" " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n", i, src, srcp, dest, destp, tw->tw_substate, 0, 0, - 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0, + 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, atomic_read(&tw->tw_refcnt), tw, len); }
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index c66b90f..aa41b0e 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c@@ -1875,7 +1875,7 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i) tp->write_seq-tp->snd_una, (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq), timer_active, - jiffies_to_clock_t(timer_expires - jiffies), + jiffies_delta_to_clock_t(timer_expires - jiffies), icsk->icsk_retransmits, sock_i_uid(sp), icsk->icsk_probes_out,
@@ -1895,10 +1895,7 @@ static void get_timewait6_sock(struct seq_file *seq, const struct in6_addr *dest, *src; __u16 destp, srcp; const struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw); - int ttd = tw->tw_ttd - jiffies; - - if (ttd < 0) - ttd = 0; + long delta = tw->tw_ttd - jiffies; dest = &tw6->tw_v6_daddr; src = &tw6->tw_v6_rcv_saddr;
@@ -1914,7 +1911,7 @@ static void get_timewait6_sock(struct seq_file *seq, dest->s6_addr32[0], dest->s6_addr32[1], dest->s6_addr32[2], dest->s6_addr32[3], destp, tw->tw_substate, 0, 0, - 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0, + 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, atomic_read(&tw->tw_refcnt), tw); }