Re: [PATCH] ipc/sem.c: prevent ENOMEM in semop() w/ SEM_UNDO flag

Hi Manfred, (2012-08-07 20:10), Manfred Spraul wrote: > Hi Seiichi, > > 2012/8/6 Seiichi Ikarashi >> >> >> A real case was as follows. >> semget(IPC_PRIVATE, 7, IPC_CREAT | IPC_EXCL); >> sops[0].sem_num = 0; >> sops[0].sem_op = 1; >> sops[0].sem_flg = SEM_UNDO; >>

Re: [PATCH] ipc/sem.c: prevent ENOMEM in semop() w/ SEM_UNDO flag

Hi Seiichi, 2012/8/6 Seiichi Ikarashi > > > A real case was as follows. > semget(IPC_PRIVATE, 7, IPC_CREAT | IPC_EXCL); > sops[0].sem_num = 0; > sops[0].sem_op = 1; > sops[0].sem_flg = SEM_UNDO; > semop(semid, sops, 1); > I think this can't work: sops[].sem_num is

Re: [PATCH] ipc/sem.c: prevent ENOMEM in semop() w/ SEM_UNDO flag

Hi Manfred, (2012-08-04 02:39), Manfred Spraul wrote: > 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

Re: [PATCH] ipc/sem.c: prevent ENOMEM in semop() w/ SEM_UNDO flag

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? still documents ~800

[PATCH] ipc/sem.c: prevent ENOMEM in semop() w/ SEM_UNDO flag

semop() with SEM_UNDO sem_flg can result in ENOMEM even after succeeding semget() with large nsems. 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: Sei