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| author | Eric Dumazet <edumazet@google.com> | 2012-08-08 21:13:53 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-08-09 16:17:03 -0700 |
| commit | a399a8053164ec8bcb06fed52be9941a26ecde11 (patch) | |
| tree | c60402a77d08c82630d63e972d32b038919b827f /net/core/rtnetlink.c | |
| parent | 79cda75a107da0d49732b5cb642b456264dd7e0e (diff) | |
| download | lwn-a399a8053164ec8bcb06fed52be9941a26ecde11.tar.gz lwn-a399a8053164ec8bcb06fed52be9941a26ecde11.zip | |
time: jiffies_delta_to_clock_t() helper to the rescue
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 <maze@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: hank <pyu@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/rtnetlink.c')
| -rw-r--r-- | net/core/rtnetlink.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 2c5a0a06c4ce..db037c9a4c48 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, |