Messages in this thread | | | Date | Fri, 03 Aug 2012 19:39:02 +0200 | From | Manfred Spraul <> | Subject | Re: [PATCH] ipc/sem.c: prevent ENOMEM in semop() w/ SEM_UNDO flag |
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Hi Seiichi,
On 08/03/2012 02:49 PM, Seiichi Ikarashi wrote: > semop() with SEM_UNDO sem_flg can result in ENOMEM even after > succeeding semget() with large nsems. How large is nsems, what is the use case? Which kind of operations are performed? Only simple semop(,,1) calls?
<linux/sem.h> still documents ~8000 as the upper limit, I'm not sure if there are other codepaths that might fail as well. If all are fixed, then the documentation should be updated as well.
> This is because > semop() uses kzalloc() via find_alloc_undo() though > semget() uses vmalloc() via ipc_rcu_alloc(). > This patch makes semop() be able to use vmalloc() via ipc_alloc(). > > Signed-off-by: Seiichi Ikarashi <s.ikarashi@jp.fujitsu.com>
-- Manfred
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