Messages in this thread Patch in this message | | | Date | Tue, 27 Jan 2009 22:57:41 -0800 (PST) | From | Davide Libenzi <> | Subject | Re: [patch 016/104] epoll: introduce resource usage limits |
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On Tue, 27 Jan 2009, Davide Libenzi wrote:
> Or, like Willy said, make (for -stable) the default unlimited, and > let sysadmins to put the bounds if they feel the DoS can apply to them.
Whose patch follows ...
- Davide
--- fs/eventpoll.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-)
Index: linux-2.6.mod/fs/eventpoll.c =================================================================== --- linux-2.6.mod.orig/fs/eventpoll.c 2009-01-27 22:40:23.000000000 -0800 +++ linux-2.6.mod/fs/eventpoll.c 2009-01-27 22:52:41.000000000 -0800 @@ -220,9 +220,9 @@ * Configuration options available inside /proc/sys/fs/epoll/ */ /* Maximum number of epoll devices, per user */ -static int max_user_instances __read_mostly; +static int max_user_instances __read_mostly = INT_MAX; /* Maximum number of epoll watched descriptors, per user */ -static int max_user_watches __read_mostly; +static int max_user_watches __read_mostly = INT_MAX; /* * This mutex is used to serialize ep_free() and eventpoll_release_file(). @@ -721,8 +721,7 @@ user = get_current_user(); error = -EMFILE; - if (unlikely(atomic_read(&user->epoll_devs) >= - max_user_instances)) + if (atomic_read(&user->epoll_devs) >= max_user_instances) goto free_uid; error = -ENOMEM; ep = kzalloc(sizeof(*ep), GFP_KERNEL); @@ -897,8 +896,7 @@ struct epitem *epi; struct ep_pqueue epq; - if (unlikely(atomic_read(&ep->user->epoll_watches) >= - max_user_watches)) + if (atomic_read(&ep->user->epoll_watches) >= max_user_watches) return -ENOSPC; if (!(epi = kmem_cache_alloc(epi_cache, GFP_KERNEL))) return -ENOMEM; @@ -1416,13 +1414,6 @@ static int __init eventpoll_init(void) { - struct sysinfo si; - - si_meminfo(&si); - max_user_instances = 128; - max_user_watches = (((si.totalram - si.totalhigh) / 32) << PAGE_SHIFT) / - EP_ITEM_COST; - /* Initialize the structure used to perform safe poll wait head wake ups */ ep_nested_calls_init(&poll_safewake_ncalls);
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