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2006-01-08[PATCH] do_coredump() should reset group_stop_count earlierOleg Nesterov
__group_complete_signal() sets ->group_stop_count in sig_kernel_coredump() path and marks the target thread as ->group_exit_task. So any thread except group_exit_task will go to handle_group_stop()->finish_stop(). However, when group_exit_task actually starts do_coredump(), it sets SIGNAL_GROUP_EXIT, but does not reset ->group_stop_count while killing other threads. If we have not yet stopped threads in the same thread group, they all will spin in kernel mode until group_exit_task sends them SIGKILL, because ->group_stop_count > 0 means: recalc_sigpending_tsk() never clears TIF_SIGPENDING get_signal_to_deliver() goes to handle_group_stop() handle_group_stop() returns when SIGNAL_GROUP_EXIT set syscall_exit/resume_userspace notice TIF_SIGPENDING, call get_signal_to_deliver() again. So we are wasting cpu cycles, and if one of these threads is rt_task() this may be a serious problem. NOTE: do_coredump() holds ->mmap_sem, so not stopped threads can't escape coredumping after clearing ->group_stop_count. See also this thread: http://marc.theaimsgroup.com/?t=112739139900002 Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08[PATCH] Fix some problems with truncate and mtime semantics.NeilBrown
SUS requires that when truncating a file to the size that it currently is: truncate and ftruncate should NOT modify ctime or mtime O_TRUNC SHOULD modify ctime and mtime. Currently mtime and ctime are always modified on most local filesystems (side effect of ->truncate) or never modified (on NFS). With this patch: ATTR_CTIME|ATTR_MTIME are sent with ATTR_SIZE precisely when an update of these times is required whether size changes or not (via a new argument to do_truncate). This allows NFS to do the right thing for O_TRUNC. inode_setattr nolonger forces ATTR_MTIME|ATTR_CTIME when the ATTR_SIZE sets the size to it's current value. This allows local filesystems to do the right thing for f?truncate. Also, the logic in inode_setattr is changed a bit so there are two return points. One returns the error from vmtruncate if it failed, the other returns 0 (there can be no other failure). Finally, if vmtruncate succeeds, and ATTR_SIZE is the only change requested, we now fall-through and mark_inode_dirty. If a filesystem did not have a ->truncate function, then vmtruncate will have changed i_size, without marking the inode as 'dirty', and I think this is wrong. Signed-off-by: Neil Brown <neilb@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08[PATCH] RCU signal handlingIngo Molnar
RCU tasklist_lock and RCU signal handling: send signals RCU-read-locked instead of tasklist_lock read-locked. This is a scalability improvement on SMP and a preemption-latency improvement under PREEMPT_RCU. Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: William Irwin <wli@holomorphy.com> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] mm: rmap optimisationNick Piggin
Optimise rmap functions by minimising atomic operations when we know there will be no concurrent modifications. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-29VM: add common helper function to create the page tablesLinus Torvalds
This logic was duplicated four times, for no good reason. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-23[PATCH] fix do_wait() vs exec() raceOleg Nesterov
When non-leader thread does exec, de_thread adds old leader to the init's ->children list in EXIT_ZOMBIE state and drops tasklist_lock. This means that release_task(leader) in de_thread() is racy vs do_wait() from init task. I think de_thread() should set old leader's state to EXIT_DEAD instead. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: george anzinger <george@mvista.com> Cc: Roland Dreier <rolandd@cisco.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09[PATCH] add a file_permission helperChristoph Hellwig
A few more callers of permission() just want to check for a different access pattern on an already open file. This patch adds a wrapper for permission() that takes a file in preparation of per-mount read-only support and to clean up the callers a little. The helper is not intended for new code, everything without the interface set in stone should use vfs_permission() Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09[PATCH] add a vfs_permission helperChristoph Hellwig
Most permission() calls have a struct nameidata * available. This helper takes that as an argument and thus makes sure we pass it down for lookup intents and prepares for per-mount read-only support where we need a struct vfsmount for checking whether a file is writeable. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-08[PATCH] fix de_thread() vs send_group_sigqueue() raceOleg Nesterov
When non-leader thread does exec, de_thread calls release_task(leader) before calling exit_itimers(). If local timer interrupt happens in between, it can oops in send_group_sigqueue() while taking ->sighand->siglock == NULL. However, we can't change send_group_sigqueue() to check p->signal != NULL, because sys_timer_create() does get_task_struct() only in SIGEV_THREAD_ID case. So it is possible that this task_struct was already freed and we can't trust p->signal. This patch changes de_thread() so that leader released after exit_itimers() call. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Chris Wright <chrisw@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[PATCH] VFS: pass file pointer to filesystem from ftruncate()Miklos Szeredi
This patch extends the iattr structure with a file pointer memeber, and adds an ATTR_FILE validity flag for this member. This is set if do_truncate() is invoked from ftruncate() or from do_coredump(). The change is source and binary compatible. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07[PATCH] Process Events ConnectorMatt Helsley
This patch adds a connector that reports fork, exec, id change, and exit events for all processes to userspace. It replaces the fork_advisor patch that ELSA is currently using. Applications that may find these events useful include accounting/auditing (e.g. ELSA), system activity monitoring (e.g. top), security, and resource management (e.g. CKRM). Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] fix de_thread() vs do_coredump() deadlockOleg Nesterov
de_thread() sends SIGKILL to all sub-threads and waits them to die in 'D' state. It is possible that one of the threads already dequeued coredump signal. When de_thread() unlocks ->sighand->lock that thread can enter do_coredump()->coredump_wait() and cause a deadlock. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] coredump_wait() cleanupOleg Nesterov
This patch deletes pointless code from coredump_wait(). 1. It does useless mm->core_waiters inc/dec under mm->mmap_sem, but any changes to ->core_waiters have no effect until we drop ->mmap_sem. 2. It calls yield() for absolutely unknown reason. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] fix de_thread vs it_real_fn() deadlockOleg Nesterov
de_thread() calls del_timer_sync(->real_timer) under ->sighand->siglock. This is deadlockable, it_real_fn sends a signal and needs this lock too. Also, delete unneeded ->real_timer.data assignment. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] little de_thread() cleanupOleg Nesterov
Trivial, saves one 'if' branch in de_thread(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29[PATCH] mm: ptd_alloc take ptlockHugh Dickins
Second step in pushing down the page_table_lock. Remove the temporary bridging hack from __pud_alloc, __pmd_alloc, __pte_alloc: expect callers not to hold page_table_lock, whether it's on init_mm or a user mm; take page_table_lock internally to check if a racing task already allocated. Convert their callers from common code. But avoid coming back to change them again later: instead of moving the spin_lock(&mm->page_table_lock) down, switch over to new macros pte_alloc_map_lock and pte_unmap_unlock, which encapsulate the mapping+locking and unlocking+unmapping together, and in the end may use alternatives to the mm page_table_lock itself. These callers all hold mmap_sem (some exclusively, some not), so at no level can a page table be whipped away from beneath them; and pte_alloc uses the "atomic" pmd_present to test whether it needs to allocate. It appears that on all arches we can safely descend without page_table_lock. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29[PATCH] mm: update_hiwaters just in timeHugh Dickins
update_mem_hiwater has attracted various criticisms, in particular from those concerned with mm scalability. Originally it was called whenever rss or total_vm got raised. Then many of those callsites were replaced by a timer tick call from account_system_time. Now Frank van Maarseveen reports that to be found inadequate. How about this? Works for Frank. Replace update_mem_hiwater, a poor combination of two unrelated ops, by macros update_hiwater_rss and update_hiwater_vm. Don't attempt to keep mm->hiwater_rss up to date at timer tick, nor every time we raise rss (usually by 1): those are hot paths. Do the opposite, update only when about to lower rss (usually by many), or just before final accounting in do_exit. Handle mm->hiwater_vm in the same way, though it's much less of an issue. Demand that whoever collects these hiwater statistics do the work of taking the maximum with rss or total_vm. And there has been no collector of these hiwater statistics in the tree. The new convention needs an example, so match Frank's usage by adding a VmPeak line above VmSize to /proc/<pid>/status, and also a VmHWM line above VmRSS (High-Water-Mark or High-Water-Memory). There was a particular anomaly during mremap move, that hiwater_vm might be captured too high. A fleeting such anomaly remains, but it's quickly corrected now, whereas before it would stick. What locking? None: if the app is racy then these statistics will be racy, it's not worth any overhead to make them exact. But whenever it suits, hiwater_vm is updated under exclusive mmap_sem, and hiwater_rss under page_table_lock (for now) or with preemption disabled (later on): without going to any trouble, minimize the time between reading current values and updating, to minimize those occasions when a racing thread bumps a count up and back down in between. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29[PATCH] mm: rss = file_rss + anon_rssHugh Dickins
I was lazy when we added anon_rss, and chose to change as few places as possible. So currently each anonymous page has to be counted twice, in rss and in anon_rss. Which won't be so good if those are atomic counts in some configurations. Change that around: keep file_rss and anon_rss separately, and add them together (with get_mm_rss macro) when the total is needed - reading two atomics is much cheaper than updating two atomics. And update anon_rss upfront, typically in memory.c, not tucked away in page_add_anon_rmap. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-18VFS: Allow the filesystem to return a full file pointer on open intentTrond Myklebust
This is needed by NFSv4 for atomicity reasons: our open command is in fact a lookup+open, so we need to be able to propagate open context information from lookup() into the resulting struct file's private_data field. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-14[PATCH] error path in setup_arg_pages() misses vm_unacct_memory()Hugh Dickins
Pavel Emelianov and Kirill Korotaev observe that fs and arch users of security_vm_enough_memory tend to forget to vm_unacct_memory when a failure occurs further down (typically in setup_arg_pages variants). These are all users of insert_vm_struct, and that reservation will only be unaccounted on exit if the vma is marked VM_ACCOUNT: which in some cases it is (hidden inside VM_STACK_FLAGS) and in some cases it isn't. So x86_64 32-bit and ppc64 vDSO ELFs have been leaking memory into Committed_AS each time they're run. But don't add VM_ACCOUNT to them, it's inappropriate to reserve against the very unlikely case that gdb be used to COW a vDSO page - we ought to do something about that in do_wp_page, but there are yet other inconsistencies to be resolved. The safe and economical way to fix this is to let insert_vm_struct do the security_vm_enough_memory check when it finds VM_ACCOUNT is set. And the MIPS irix_brk has been calling security_vm_enough_memory before calling do_brk which repeats it, doubly accounting and so also leaking. Remove that, and all the fs and arch calls to security_vm_enough_memory: give it a less misleading name later on. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-Off-By: Kirill Korotaev <dev@sw.ru> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-14[PATCH] Fix fs/exec.c:788 (de_thread()) BUG_ONAlexander Nyberg
It turns out that the BUG_ON() in fs/exec.c: de_thread() is unreliable and can trigger due to the test itself being racy. de_thread() does while (atomic_read(&sig->count) > count) { } ..... ..... BUG_ON(!thread_group_empty(current)); but release_task does write_lock_irq(&tasklist_lock) __exit_signal (this is where atomic_dec(&sig->count) is run) __exit_sighand __unhash_process takes write lock on tasklist_lock remove itself out of PIDTYPE_TGID list write_unlock_irq(&tasklist_lock) so there's a clear (although small) window between the atomic_dec(&sig->count) and the actual PIDTYPE_TGID unhashing of the thread. And actually there is no need for all threads to have exited at this point, so we simply kill the BUG_ON. Big thanks to Marc Lehmann who provided the test-case. Fixes Bug 5170 (http://bugme.osdl.org/show_bug.cgi?id=5170) Signed-off-by: Alexander Nyberg <alexn@telia.com> Cc: Roland McGrath <roland@redhat.com> Cc: Andrew Morton <akpm@osdl.org> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] files: break up files structDipankar Sarma
In order for the RCU to work, the file table array, sets and their sizes must be updated atomically. Instead of ensuring this through too many memory barriers, we put the arrays and their sizes in a separate structure. This patch takes the first step of putting the file table elements in a separate structure fdtable that is embedded withing files_struct. It also changes all the users to refer to the file table using files_fdtable() macro. Subsequent applciation of RCU becomes easier after this. Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-12[PATCH] reset real_timer target on exec leader changeRoland McGrath
When a noninitial thread does exec, it becomes the new group leader. If there is a ITIMER_REAL timer running, it points at the old group leader and when it fires it can follow a stale pointer. The timer data needs to be reset to point at the exec'ing thread that is becoming the group leader. This has to synchronize with any concurrent firing of the timer to make sure that it_real_fn can never run when the data points to a thread that might have been reaped already. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23[PATCH] setuid core dumpAlan Cox
Add a new `suid_dumpable' sysctl: This value can be used to query and set the core dump mode for setuid or otherwise protected/tainted binaries. The modes are 0 - (default) - traditional behaviour. Any process which has changed privilege levels or is execute only will not be dumped 1 - (debug) - all processes dump core when possible. The core dump is owned by the current user and no security is applied. This is intended for system debugging situations only. Ptrace is unchecked. 2 - (suidsafe) - any binary which normally would not be dumped is dumped readable by root only. This allows the end user to remove such a dump but not access it directly. For security reasons core dumps in this mode will not overwrite one another or other files. This mode is appropriate when adminstrators are attempting to debug problems in a normal environment. (akpm: > > +EXPORT_SYMBOL(suid_dumpable); > > EXPORT_SYMBOL_GPL? No problem to me. > > if (current->euid == current->uid && current->egid == current->gid) > > current->mm->dumpable = 1; > > Should this be SUID_DUMP_USER? Actually the feedback I had from last time was that the SUID_ defines should go because its clearer to follow the numbers. They can go everywhere (and there are lots of places where dumpable is tested/used as a bool in untouched code) > Maybe this should be renamed to `dump_policy' or something. Doing that > would help us catch any code which isn't using the #defines, too. Fair comment. The patch was designed to be easy to maintain for Red Hat rather than for merging. Changing that field would create a gigantic diff because it is used all over the place. ) Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-18Clean up subthread execLinus Torvalds
Make sure we re-parent itimers, and use BUG_ON() instead of an explicit conditional BUG().
2005-05-05[PATCH] comments on locking of task->commPaolo 'Blaisorblade' Giarrusso
Add some comments about task->comm, to explain what it is near its definition and provide some important pointers to its uses. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-05[PATCH] make some things staticAdrian Bunk
This patch makes some needlessly global identifiers static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: Arjan van de Ven <arjanv@infradead.org> Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!