user/sven/linux.git/include/linux/shm.h, branch v3.4.78

shm: handle separate PID namespaces case

2011-07-30T18:44:19Z

shm_try_destroy_orphaned() and shm_try_destroy_current() didn't handle the case of separate PID namespaces, but a single IPC namespace. If there are tasks with the same PID values using the same shmem object, the wrong destroy decision could be reached. On shm segment creation store the pointer to the creator task in shmid_kernel->shm_creator field and zero it on task exit. Then use the ->shm_creator insread of shm_cprid in both functions. As shmid_kernel object is already locked at this stage, no additional locking is needed. Signed-off-by: Vasiliy Kulikov Acked-by: Serge Hallyn Signed-off-by: Linus Torvalds

ipc: introduce shm_rmid_forced sysctl

2011-07-26T23:49:44Z

Add support for the shm_rmid_forced sysctl. If set to 1, all shared memory objects in current ipc namespace will be automatically forced to use IPC_RMID. The POSIX way of handling shmem allows one to create shm objects and call shmdt(), leaving shm object associated with no process, thus consuming memory not counted via rlimits. With shm_rmid_forced=1 the shared memory object is counted at least for one process, so OOM killer may effectively kill the fat process holding the shared memory. It obviously breaks POSIX - some programs relying on the feature would stop working. So set shm_rmid_forced=1 only if you're sure nobody uses "orphaned" memory. Use shm_rmid_forced=0 by default for compatability reasons. The feature was previously impemented in -ow as a configure option. [akpm@linux-foundation.org: fix documentation, per Randy] [akpm@linux-foundation.org: fix warning] [akpm@linux-foundation.org: readability/conventionality tweaks] [akpm@linux-foundation.org: fix shm_rmid_forced/shm_forced_rmid confusion, use standard comment layout] Signed-off-by: Vasiliy Kulikov Cc: Randy Dunlap Cc: "Eric W. Biederman" Cc: "Serge E. Hallyn" Cc: Daniel Lezcano Cc: Oleg Nesterov Cc: Tejun Heo Cc: Ingo Molnar Cc: Alan Cox Cc: Solar Designer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Unexport asm/page.h

2008-02-07T16:42:30Z

Do not export asm/page.h during make headers_install. This removes PAGE_SIZE from userspace headers. Signed-off-by: Kirill A. Shutemov Reviewed-by: David Woodhouse Cc: David Howells Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Thomas Gleixner Cc: Ingo Molnar Cc: H. Peter Anvin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: store ipcs into IDRs

2007-10-19T18:53:44Z

This patch introduces ipcs storage into IDRs. The main changes are: . This ipc_ids structure is changed: the entries array is changed into a root idr structure. . The grow_ary() routine is removed: it is not needed anymore when adding an ipc structure, since we are now using the IDR facility. . The ipc_rmid() routine interface is changed: . there is no need for this routine to return the pointer passed in as argument: it is now declared as a void . since the id is now part of the kern_ipc_perm structure, no need to have it as an argument to the routine Signed-off-by: Nadia Derbey Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

unexport asm/shmparam.h

2007-10-17T15:42:47Z

SHMLBA cant possible be used in userspace, see sparc versions of that header. Do not export asm/shmparam.h during make headers_install_all This removes another uservisible place of PAGE_SIZE Signed-off-by: Olaf Hering Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: "David S. Miller" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Fix get_unmapped_area and fsync for hugetlb shm segments

2007-03-02T01:18:39Z

This patch provides the following hugetlb-related fixes to the recent stacked shm files changes: - Update is_file_hugepages() so it will reconize hugetlb shm segments. - get_unmapped_area must be called with the nested file struct to handle the sfd->file->f_ops->get_unmapped_area == NULL case. - The fsync f_op must be wrapped since it is specified in the hugetlbfs f_ops. This is based on proposed fixes from Eric Biederman that were debugged and tested by me. Without it, attempting to use hugetlb shared memory segments on powerpc (and likely ia64) will kill your box. Signed-off-by: Adam Litke Cc: Eric Biederman Cc: Andrew Morton Acked-by: William Irwin Signed-off-by: Linus Torvalds

[PATCH] SHM_NORESERVE flags for shmget()

2005-11-07T15:53:37Z

Add SHM_NORESERVE functionality similar to MAP_NORESERVE for shared memory segments. This is mainly to avoid abuse of OVERCOMMIT_ALWAYS and this flag is ignored for OVERCOMMIT_NEVER. Signed-off-by: Badari Pulavarty Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] hugetlb: permit executable mappings

2004-08-24T04:28:18Z

During the kernel summit, some discussion was had about the support requirements for a userspace program loader that loads executables into hugetlb on behalf of a major application (Oracle). In order to support this in a robust fashion, the cleanup of the hugetlb must be robust in the presence of disorderly termination of the programs (e.g. kill -9). Hence, the cleanup semantics are those of System V shared memory, but Linux' System V shared memory needs one critical extension for this use: executability. The following microscopic patch enables this major application to provide robust hugetlb cleanup. Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] rlimit-based mlocks for unprivileged users

2004-08-23T06:06:46Z

Here is the last agreed-on patch that lets normal users mlock pages up to their rlimit. This patch addresses all the issues brought up by Chris and Andrea. From: Chris Wright Couple more nits. The default lockable amount is one page now (first patch is was 0). Why don't we keep it as 0, with the CAP_IPC_LOCK overrides in place? That way nothing is changed from user perspective, and the rest of the policy can be done by userspace as it should. This patch breaks in one scenario. When ulimit == 0, process has CAP_IPC_LOCK, and does SHM_LOCK. The subsequent unlock or destroy will corrupt the locked_shm count. It's also inconsistent in handling user_can_mlock/CAP_IPC_LOCK interaction betwen shm_lock and shm_hugetlb. SHM_HUGETLB can now only be done by the shm_group or CAP_IPC_LOCK. Not any can_do_mlock() user. Double check of can_do_mlock isn't needed in SHM_LOCK path. Interface names user_can_mlock and user_substract_mlock could be better. Incremental update below. Ran some simple sanity tests on this plus my patch below and didn't find any problems. * Make default RLIM_MEMLOCK limit 0. * Move CAP_IPC_LOCK check into user_can_mlock to be consistent and fix but with ulimit == 0 && CAP_IPC_LOCK with SHM_LOCK. * Allow can_do_mlock() user to try SHM_HUGETLB setup. * Remove unecessary extra can_do_mlock() test in shmem_lock(). * Rename user_can_mlock to user_shm_lock and user_subtract_mlock to user_shm_unlock. * Use user instead of current->user to fit in 80 cols on SHM_LOCK. Signed-off-by: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] add syscalls.h

2004-02-25T00:12:24Z

From: "Randy.Dunlap" Add syscalls.h, which contains prototypes for the kernel's system calls. Replace open-coded declarations all over the place. This patch found a couple of prior bugs. It appears to be more important with -mregparm=3 as we discover more asmlinkage mismatches. Some syscalls have arch-dependent arguments, so their prototypes are in the arch-specific unistd.h. Maybe it should have been asm/syscalls.h, but there were already arch-specific syscall prototypes in asm/unistd.h... Tested on x86, ia64, x86_64, ppc64, s390 and sparc64. May cause trivial-to-fix build breakage on other architectures.