linux/ipc/util.c, branch v3.14

ipc: delete seq_max field in struct ipc_ids

2014-01-28T05:02:40Z

This field is only used to reset the ids seq number if it exceeds the smaller of INT_MAX/SEQ_MULTIPLIER and USHRT_MAX, and can therefore be moved out of the structure and into its own macro. Since each ipc_namespace contains a table of 3 pointers to struct ipc_ids we can save space in instruction text: text data bss dec hex filename 56232 2348 24 58604 e4ec ipc/built-in.o 56216 2348 24 58588 e4dc ipc/built-in.o-after Signed-off-by: Davidlohr Bueso Reviewed-by: Jonathan Gonzalez Cc: Aswin Chandramouleeswaran Cc: Rik van Riel Acked-by: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: simplify sysvipc_proc_open() return

2014-01-28T05:02:40Z

Get rid of silly/useless label jumping. Signed-off-by: Davidlohr Bueso Cc: Aswin Chandramouleeswaran Cc: Rik van Riel Acked-by: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: remove useless return statement

2014-01-28T05:02:40Z

Only found in ipc_rmid(). Signed-off-by: Davidlohr Bueso Cc: Aswin Chandramouleeswaran Cc: Rik van Riel Acked-by: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: remove braces for single statements

2014-01-28T05:02:39Z

Deal with checkpatch messages: WARNING: braces {} are not necessary for single statement blocks Signed-off-by: Davidlohr Bueso Cc: Aswin Chandramouleeswaran Cc: Rik van Riel Acked-by: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: standardize code comments

2014-01-28T05:02:39Z

IPC commenting style is all over the place, *specially* in util.c. This patch orders things a bit. Signed-off-by: Davidlohr Bueso Cc: Aswin Chandramouleeswaran Cc: Rik van Riel Acked-by: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: whitespace cleanup

2014-01-28T05:02:39Z

The ipc code does not adhere the typical linux coding style. This patch fixes lots of simple whitespace errors. - mostly autogenerated by scripts/checkpatch.pl -f --fix \ --types=pointer_location,spacing,space_before_tab - one manual fixup (keep structure members tab-aligned) - removal of additional space_before_tab that were not found by --fix Tested with some of my msg and sem test apps. Andrew: Could you include it in -mm and move it towards Linus' tree? Signed-off-by: Manfred Spraul Suggested-by: Li Bin Cc: Joe Perches Acked-by: Rafael Aquini Cc: Davidlohr Bueso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: change kern_ipc_perm.deleted type to bool

2014-01-28T05:02:39Z

struct kern_ipc_perm.deleted is meant to be used as a boolean toggle, and the changes introduced by this patch are just to make the case explicit. Signed-off-by: Rafael Aquini Reviewed-by: Rik van Riel Cc: Greg Thelen Acked-by: Davidlohr Bueso Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc/util.c: remove unnecessary work pending test

2013-11-13T03:09:36Z

Remove unnecessary work pending test before calling schedule_work(). It has been tested in queue_work_on() already. No functional changed. Signed-off-by: Xie XiuQi Cc: Tejun Heo Reviewed-by: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: update locking scheme comments

2013-10-17T04:35:52Z

The initial documentation was a bit incomplete, update accordingly. [akpm@linux-foundation.org: make it more readable in 80 columns] Signed-off-by: Davidlohr Bueso Acked-by: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: fix race with LSMs

2013-09-24T16:36:53Z

Currently, IPC mechanisms do security and auditing related checks under RCU. However, since security modules can free the security structure, for example, through selinux_[sem,msg_queue,shm]_free_security(), we can race if the structure is freed before other tasks are done with it, creating a use-after-free condition. Manfred illustrates this nicely, for instance with shared mem and selinux: -> do_shmat calls rcu_read_lock() -> do_shmat calls shm_object_check(). Checks that the object is still valid - but doesn't acquire any locks. Then it returns. -> do_shmat calls security_shm_shmat (e.g. selinux_shm_shmat) -> selinux_shm_shmat calls ipc_has_perm() -> ipc_has_perm accesses ipc_perms->security shm_close() -> shm_close acquires rw_mutex & shm_lock -> shm_close calls shm_destroy -> shm_destroy calls security_shm_free (e.g. selinux_shm_free_security) -> selinux_shm_free_security calls ipc_free_security(&shp->shm_perm) -> ipc_free_security calls kfree(ipc_perms->security) This patch delays the freeing of the security structures after all RCU readers are done. Furthermore it aligns the security life cycle with that of the rest of IPC - freeing them based on the reference counter. For situations where we need not free security, the current behavior is kept. Linus states: "... the old behavior was suspect for another reason too: having the security blob go away from under a user sounds like it could cause various other problems anyway, so I think the old code was at least _prone_ to bugs even if it didn't have catastrophic behavior." I have tested this patch with IPC testcases from LTP on both my quad-core laptop and on a 64 core NUMA server. In both cases selinux is enabled, and tests pass for both voluntary and forced preemption models. While the mentioned races are theoretical (at least no one as reported them), I wanted to make sure that this new logic doesn't break anything we weren't aware of. Suggested-by: Linus Torvalds Signed-off-by: Davidlohr Bueso Acked-by: Manfred Spraul Signed-off-by: Linus Torvalds