On a 16TB machine, max_user_watches has an integer overflow. Convert it to use a long and handle the associated fallout. Signed-off-by: Robin Holt To: Andrew Morton Cc: "Eric W. Biederman" Cc: Davide Libenzi Cc: linux-kernel@vger.kernel.org Cc: Pekka Enberg --- fs/eventpoll.c | 20 ++++++++++++-------- include/linux/sched.h | 2 +- 2 files changed, 13 insertions(+), 9 deletions(-) Index: pv1010933/fs/eventpoll.c =================================================================== --- pv1010933.orig/fs/eventpoll.c 2010-10-27 14:04:44.000000000 -0500 +++ pv1010933/fs/eventpoll.c 2010-10-27 14:07:50.211457551 -0500 @@ -220,7 +220,7 @@ struct ep_send_events_data { * Configuration options available inside /proc/sys/fs/epoll/ */ /* Maximum number of epoll watched descriptors, per user */ -static int max_user_watches __read_mostly; +static long max_user_watches __read_mostly; /* * This mutex is used to serialize ep_free() and eventpoll_release_file(). @@ -243,16 +243,18 @@ static struct kmem_cache *pwq_cache __re #include -static int zero; +static long zero; +static long long_max = LONG_MAX; ctl_table epoll_table[] = { { .procname = "max_user_watches", .data = &max_user_watches, - .maxlen = sizeof(int), + .maxlen = sizeof(max_user_watches), .mode = 0644, - .proc_handler = proc_dointvec_minmax, + .proc_handler = proc_doulongvec_minmax, .extra1 = &zero, + .extra2 = &long_max, }, { } }; @@ -564,7 +566,7 @@ static int ep_remove(struct eventpoll *e /* At this point it is safe to free the eventpoll item */ kmem_cache_free(epi_cache, epi); - atomic_dec(&ep->user->epoll_watches); + atomic_long_dec(&ep->user->epoll_watches); return 0; } @@ -900,11 +902,12 @@ static int ep_insert(struct eventpoll *e { int error, revents, pwake = 0; unsigned long flags; + long user_watches; struct epitem *epi; struct ep_pqueue epq; - if (unlikely(atomic_read(&ep->user->epoll_watches) >= - max_user_watches)) + user_watches = atomic_long_read(&ep->user->epoll_watches); + if (unlikely(user_watches >= max_user_watches)) return -ENOSPC; if (!(epi = kmem_cache_alloc(epi_cache, GFP_KERNEL))) return -ENOMEM; @@ -968,7 +971,7 @@ static int ep_insert(struct eventpoll *e spin_unlock_irqrestore(&ep->lock, flags); - atomic_inc(&ep->user->epoll_watches); + atomic_long_inc(&ep->user->epoll_watches); /* We have to call this outside the lock */ if (pwake) @@ -1422,6 +1425,7 @@ static int __init eventpoll_init(void) */ max_user_watches = (((si.totalram - si.totalhigh) / 25) << PAGE_SHIFT) / EP_ITEM_COST; + BUG_ON(max_user_watches < 0); /* Initialize the structure used to perform safe poll wait head wake ups */ ep_nested_calls_init(&poll_safewake_ncalls); Index: pv1010933/include/linux/sched.h =================================================================== --- pv1010933.orig/include/linux/sched.h 2010-10-27 14:04:44.000000000 -0500 +++ pv1010933/include/linux/sched.h 2010-10-27 14:04:47.119415143 -0500 @@ -666,7 +666,7 @@ struct user_struct { atomic_t inotify_devs; /* How many inotify devs does this user have opened? */ #endif #ifdef CONFIG_EPOLL - atomic_t epoll_watches; /* The number of file descriptors currently watched */ + atomic_long_t epoll_watches; /* The number of file descriptors currently watched */ #endif #ifdef CONFIG_POSIX_MQUEUE /* protected by mq_lock */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/