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* [PATCH] Fix sigaltstack corruption among cloned threadsGOTO Masanori2006-03-141-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes alternate signal stack corruption among cloned threads with CLONE_SIGHAND (and CLONE_VM) for linux-2.6.16-rc6. The value of alternate signal stack is currently inherited after a call of clone(... CLONE_SIGHAND | CLONE_VM). But if sigaltstack is set by a parent thread, and then if multiple cloned child threads (+ parent threads) call signal handler at the same time, some threads may be conflicted - because they share to use the same alternative signal stack region. Finally they get sigsegv. It's an undesirable race condition. Note that child threads created from NPTL pthread_create() also hit this conflict when the parent thread uses sigaltstack, without my patch. To fix this problem, this patch clears the child threads' sigaltstack information like exec(). This behavior follows the SUSv3 specification. In SUSv3, pthread_create() says "The alternate stack shall not be inherited (when new threads are initialized)". It means that sigaltstack should be cleared when sigaltstack memory space is shared by cloned threads with CLONE_SIGHAND. Note that I chose "if (clone_flags & CLONE_SIGHAND)" line because: - If clone_flags line is not existed, fork() does not inherit sigaltstack. - CLONE_VM is another choice, but vfork() does not inherit sigaltstack. - CLONE_SIGHAND implies CLONE_VM, and it looks suitable. - CLONE_THREAD is another candidate, and includes CLONE_SIGHAND + CLONE_VM, but this flag has a bit different semantics. I decided to use CLONE_SIGHAND. [ Changed to test for CLONE_VM && !CLONE_VFORK after discussion --Linus ] Signed-off-by: GOTO Masanori <gotom@sanori.org> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Linus Torvalds <torvalds@osdl.org> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Jakub Jelinek <jakub@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] remove __put_task_struct_cb export againChristoph Hellwig2006-03-111-1/+3
| | | | | | | | | | | | | | | | | | | The patch '[PATCH] RCU signal handling' [1] added an export for __put_task_struct_cb, a put_task_struct helper newly introduced in that patch. But the put_task_struct couldn't be used modular previously as __put_task_struct wasn't exported. There are not callers of it in modular code, and it shouldn't be exported because we don't want drivers to hold references to task_structs. This patch removes the export and folds __put_task_struct into __put_task_struct_cb as there's no other caller. [1] http://www2.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e56d090310d7625ecb43a1eeebd479f04affb48b Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix kill_proc_info() vs fork() theoretical raceOleg Nesterov2006-02-151-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | copy_process: attach_pid(p, PIDTYPE_PID, p->pid); attach_pid(p, PIDTYPE_TGID, p->tgid); What if kill_proc_info(p->pid) happens in between? copy_process() holds current->sighand.siglock, so we are safe in CLONE_THREAD case, because current->sighand == p->sighand. Otherwise, p->sighand is unlocked, the new process is already visible to the find_task_by_pid(), but have a copy of parent's 'struct pid' in ->pids[PIDTYPE_TGID]. This means that __group_complete_signal() may hang while doing do ... while (next_thread() != p) We can solve this problem if we reverse these 2 attach_pid()s: attach_pid() does wmb() group_send_sig_info() calls spin_lock(), which provides a read barrier. // Yes ? I don't think we can hit this race in practice, but still. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix kill_proc_info() vs CLONE_THREAD raceOleg Nesterov2006-02-151-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | There is a window after copy_process() unlocks ->sighand.siglock and before it adds the new thread to the thread list. In that window __group_complete_signal(SIGKILL) will not see the new thread yet, so this thread will start running while the whole thread group was supposed to exit. I beleive we have another good reason to place attach_pid(PID/TGID) under ->sighand.siglock. We can do the same for release_task()->__unhash_process() de_thread()->switch_exec_pids() After that we don't need tasklist_lock to iterate over the thread list, and we can simplify things, see for example do_sigaction() or sys_times(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unshare system call -v5: unshare filesJANAK DESAI2006-02-071-30/+51
| | | | | | | | | | | | | | If the file descriptor structure is being shared, allocate a new one and copy information from the current, shared, structure. Signed-off-by: Janak Desai <janak@us.ibm.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unshare system call -v5: unshare vmJANAK DESAI2006-02-071-31/+56
| | | | | | | | | | | | | | If vm structure is being shared, allocate a new one and copy information from the current, shared, structure. Signed-off-by: Janak Desai <janak@us.ibm.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unshare system call -v5: unshare namespaceJANAK DESAI2006-02-071-6/+11
| | | | | | | | | | | | | | If the namespace structure is being shared, allocate a new one and copy information from the current, shared, structure. Signed-off-by: Janak Desai <janak@us.ibm.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unshare system call -v5: unshare filesystem infoJANAK DESAI2006-02-071-3/+6
| | | | | | | | | | | | | | If filesystem structure is being shared, allocate a new one and copy information from the current, shared, structure. Signed-off-by: Janak Desai <janak@us.ibm.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unshare system call -v5: system call handler functionJANAK DESAI2006-02-071-0/+232
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sys_unshare system call handler function accepts the same flags as clone system call, checks constraints on each of the flags and invokes corresponding unshare functions to disassociate respective process context if it was being shared with another task. Here is the link to a program for testing unshare system call. http://prdownloads.sourceforge.net/audit/unshare_test.c?download Please note that because of a problem in rmdir associated with bind mounts and clone with CLONE_NEWNS, the test fails while trying to remove temporary test directory. You can remove that temporary directory by doing rmdir, twice, from the command line. The first will fail with EBUSY, but the second will succeed. I have reported the problem to Ram Pai and Al Viro with a small program which reproduces the problem. Al told us yesterday that he will be looking at the problem soon. I have tried multiple rmdirs from the unshare_test program itself, but for some reason that is not working. Doing two rmdirs from command line does seem to remove the directory. Signed-off-by: Janak Desai <janak@us.ibm.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] hrtimers: cleanups and simplificationsGeorge Anzinger2006-02-011-1/+1
| | | | | | | | | | | | Clean up the interface to hrtimers by changing the init code to pass the mode as well as the clock. This allow the init code to select the correct base and eliminates extra timer re-init code in posix-timers. We also simplify the restart interface nanosleep use. Signed-off-by: George Anzinger <george@mvista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] x86_64: Inclusion of ScaleMP vSMP architecture patches - vsmp_alignRavikiran G Thirumalai2006-01-111-1/+5
| | | | | | | | | | | | | | vSMP specific alignment patch to 1. Define INTERNODE_CACHE_SHIFT for vSMP 2. Use this for alignment of critical structures 3. Use INTERNODE_CACHE_SHIFT for ARCH_MIN_TASKALIGN, and let the slab align task_struct allocations to the internode cacheline size 4. Introduce and use ARCH_MIN_MMSTRUCT_ALIGN for mm_struct slab allocations. Signed-off-by: Ravikiran Thirumalai <kiran@scalemp.com> Signed-off-by: Shai Fultheim <shai@scalemp.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] move capable() to capability.hRandy.Dunlap2006-01-111-0/+1
| | | | | | | | | | | | | - Move capable() from sched.h to capability.h; - Use <linux/capability.h> where capable() is used (in include/, block/, ipc/, kernel/, a few drivers/, mm/, security/, & sound/; many more drivers/ to go) Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] hrtimer: switch itimers to hrtimerThomas Gleixner2006-01-101-3/+3
| | | | | | | | | switch itimers to a hrtimers-based implementation Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mutex subsystem, debugging codeIngo Molnar2006-01-091-0/+4
| | | | | | | mutex implementation - add debugging code. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@infradead.org>
* [PATCH] copy_process: error path cleanupOleg Nesterov2006-01-081-6/+2
| | | | | | | | | | This patch moves 'fork_out:' under 'bad_fork_free:', and removes now unneeded 'if (retval)' check. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fork: fix race in setting child's pgrp and ttyOren Laadan2006-01-081-6/+3
| | | | | | | | | | | | | In fork, child should recopy parent's pgrp/tty after it has tasklist_lock. Otherwise following a setpgid() on the parent, *after* copy_signal(), the child will own a stale pgrp (which may be reused); (eg. if copy_mm() sleeps a long while due to memory pressure). Similar issue for the tty. Signed-off-by: Oren Laadan <orenl@cs.columbia.edu> Cc: 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>
* [PATCH] cpuset: fork hook fixPaul Jackson2006-01-081-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | Fix obscure, never seen in real life, cpuset fork race. The cpuset_fork() call in fork.c was setting up the correct task->cpuset pointer after the tasklist_lock was dropped, which briefly exposed the newly forked process with an unsafe (copied from parent without locks or usage counter increment) cpuset pointer. In theory, that exposed cpuset pointer could have been pointing at a cpuset that was already freed and removed, and in theory another task that had been sitting on the tasklist_lock waiting to scan the task list could have raced down the entire tasklist, found our new child at the far end, and dereferenced that bogus cpuset pointer. To fix, setup up the correct cpuset pointer in the new child by calling cpuset_fork() before the new task is linked into the tasklist, and with that, add a fork failure case, to dereference that cpuset, if the fork fails along the way, after cpuset_fork() was called. Had to remove a BUG_ON() from cpuset_exit(), because it was no longer valid - the call to cpuset_exit() from a failed fork would not have PF_EXITING set. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] RCU signal handlingIngo Molnar2006-01-081-1/+9
| | | | | | | | | | | | | | 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>
* [PATCH] cpuset fork locking fixPaul Jackson2005-11-281-2/+1
| | | | | | | | | | | | | Move the cpuset_fork() call below the write_unlock_irq call in kernel/fork.c copy_process(). Since the cpuset-dual-semaphore-locking-overhaul.patch, the cpuset_fork() routine acquires task_lock(), so cannot be called while holding the tasklist_lock for write. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fork.c: proc_fork_connector() called under write_lock()Andrew Morton2005-11-281-1/+1
| | | | | | | | | | Don't do that - it does GFP_KERNEL allocations, for a start. (Reported by Guillaume Thouvenin <guillaume.thouvenin@bull.net>) Acked-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unpaged: copy_page_range vmaHugh Dickins2005-11-221-1/+1
| | | | | | | | | For copy_one_pte's print_bad_pte to show the task correctly (instead of "???"), dup_mmap must pass down parent vma rather than child vma. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] aio: remove kioctx from mm_structZach Brown2005-11-131-1/+0
| | | | | | | | | | | | | | | | | | | | | | Sync iocbs have a life cycle that don't need a kioctx. Their retrying, if any, is done in the context of their owner who has allocated them on the stack. The sole user of a sync iocb's ctx reference was aio_complete() checking for an elevated iocb ref count that could never happen. No path which grabs an iocb ref has access to sync iocbs. If we were to implement sync iocb cancelation it would be done by the owner of the iocb using its on-stack reference. Removing this chunk from aio_complete allows us to remove the entire kioctx instance from mm_struct, reducing its size by a third. On a i386 testing box the slab size went from 768 to 504 bytes and from 5 to 8 per page. Signed-off-by: Zach Brown <zach.brown@oracle.com> Acked-by: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] m68k: introduce setup_thread_stack() and end_of_stack()Al Viro2005-11-131-2/+1
| | | | | | | | | | | | encapsulates the rest of arch-dependent operations with thread_info access. Two new helpers - setup_thread_stack() and end_of_stack(). For normal case the former consists of copying thread_info of parent to new thread_info and the latter returns pointer immediately past the end of thread_info. Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] m68k: introduce task_thread_infoAl Viro2005-11-131-2/+2
| | | | | | | | | | | | | | | new helper - task_thread_info(task). On platforms that have thread_info allocated separately (i.e. in default case) it simply returns task->thread_info. m68k wants (and for good reasons) to embed its thread_info into task_struct. So it will (in later patch) have task_thread_info() of its own. For now we just add a macro for generic case and convert existing instances of its body in core kernel to uses of new macro. Obviously safe - all normal architectures get the same preprocessor output they used to get. Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SPARC64] mm: context switch ptlockHugh Dickins2005-11-071-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | sparc64 is unique among architectures in taking the page_table_lock in its context switch (well, cris does too, but erroneously, and it's not yet SMP anyway). This seems to be a private affair between switch_mm and activate_mm, using page_table_lock as a per-mm lock, without any relation to its uses elsewhere. That's fine, but comment it as such; and unlock sooner in switch_mm, more like in activate_mm (preemption is disabled here). There is a block of "if (0)"ed code in smp_flush_tlb_pending which would have liked to rely on the page_table_lock, in switch_mm and elsewhere; but its comment explains how dup_mmap's flush_tlb_mm defeated it. And though that could have been changed at any time over the past few years, now the chance vanishes as we push the page_table_lock downwards, and perhaps split it per page table page. Just delete that block of code. Which leaves the mysterious spin_unlock_wait(&oldmm->page_table_lock) in kernel/fork.c copy_mm. Textual analysis (supported by Nick Piggin) suggests that the comment was written by DaveM, and that it relates to the defeated approach in the sparc64 smp_flush_tlb_pending. Just delete this block too. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] Process Events ConnectorMatt Helsley2005-11-071-0/+2
| | | | | | | | | | | | 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>
* [PATCH] mm: ptd_alloc take ptlockHugh Dickins2005-10-291-2/+0
| | | | | | | | | | | | | | | | | | | | | | 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>
* [PATCH] mm: dup_mmap down new mmap_semHugh Dickins2005-10-291-5/+4
| | | | | | | | | | | | | | One anomaly remains from when Andrea rationalized the responsibilities of mmap_sem and page_table_lock: in dup_mmap we add vmas to the child holding its page_table_lock, but not the mmap_sem which normally guards the vma list and rbtree. Which could be an issue for unuse_mm: though since it just walks down the list (today with page_table_lock, tomorrow not), it's probably okay. Will need a memory barrier? Oh, keep it simple, Nick and I agreed, no harm in taking child's mmap_sem here. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm: dup_mmap use oldmm moreHugh Dickins2005-10-291-6/+6
| | | | | | | | | | Use the parent's oldmm throughout dup_mmap, instead of perversely going back to current->mm. (Can you hear the sigh of relief from those mpnts? Usually I squash them, but not today.) Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm: rss = file_rss + anon_rssHugh Dickins2005-10-291-2/+2
| | | | | | | | | | | | | | | | 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>
* [PATCH] mm: mm_init set_mm_countersHugh Dickins2005-10-291-2/+2
| | | | | | | | | | | | How is anon_rss initialized? In dup_mmap, and by mm_alloc's memset; but that's not so good if an mm_counter_t is a special type. And how is rss initialized? By set_mm_counter, all over the place. Come on, we just need to initialize them both at once by set_mm_counter in mm_init (which follows the memcpy when forking). Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm: vm_stat_account unshackledHugh Dickins2005-10-291-1/+1
| | | | | | | | | | The original vm_stat_account has fallen into disuse, with only one user, and only one user of vm_stat_unaccount. It's easier to keep track if we convert them all to __vm_stat_account, then free it from its __shackles. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Threads shouldn't inherit PF_NOFREEZEAlan Stern2005-10-191-1/+1
| | | | | | | | | | | | | | | | The PF_NOFREEZE process flag should not be inherited when a thread is forked. This patch (as585) removes the flag from the child. This problem is starting to show up more and more as drivers turn to the kthread API instead of using kernel_thread(). As a result, their kernel threads are now children of the kthread worker instead of modprobe, and they inherit the PF_NOFREEZE flag. This can cause problems during system suspend; the kernel threads are not getting frozen as they ought to be. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] CPU hotplug breaks wake_up_new_taskSrivatsa Vaddagiri2005-09-171-1/+2
| | | | | | | | | | | Fix a problem wherein a new-born task is added to a dead CPU. Signed-off-by: Srivatsa Vaddagiri <vatsa@in.ibm.com> Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Acked-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] files: files struct with RCUDipankar Sarma2005-09-091-6/+17
| | | | | | | | | | | | | | | | | | | | | Patch to eliminate struct files_struct.file_lock spinlock on the reader side and use rcu refcounting rcuref_xxx api for the f_count refcounter. The updates to the fdtable are done by allocating a new fdtable structure and setting files->fdt to point to the new structure. The fdtable structure is protected by RCU thereby allowing lock-free lookup. For fd arrays/sets that are vmalloced, we use keventd to free them since RCU callbacks can't sleep. A global list of fdtable to be freed is not scalable, so we use a per-cpu list. If keventd is already handling the current cpu's work, we use a timer to defer queueing of that work. Since the last publication, this patch has been re-written to avoid using explicit memory barriers and use rcu_assign_pointer(), rcu_dereference() premitives instead. This required that the fd information is kept in a separate structure (fdtable) and updated atomically. Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] files: break up files structDipankar Sarma2005-09-091-32/+50
| | | | | | | | | | | | | | | 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>
* [PATCH] fix disassociate_ctty vs. fork raceJason Baron2005-09-091-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Race is as follows. Process A forks process B, both being part of the same session. Then, A calls disassociate_ctty while B forks C: A B ==== ==== fork() copy_signal() dissasociate_ctty() .... attach_pid(p, PIDTYPE_SID, p->signal->session); Now, C can have current->signal->tty pointing to a freed tty structure, as it hasn't yet been added to the session group (to have its controlling tty cleared on the diassociate_ctty() call). This has shown up as an oops but could be even more serious. I haven't tried to create a test case, but a customer has verified that the patch below resolves the issue, which was occuring quite frequently. I'll try and post the test case if i can. The patch simply checks for a NULL tty *after* it has been attached to the proper session group and clears it as necessary. Alternatively, we could simply do the tty assignment after the the process is added to the proper session group. Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Clear task_struct->fs_excl on fork()Giancarlo Formicuccia2005-09-091-0/+1
| | | | | | | | | An oversight. We don't want to carry the IO scheduler's "we hold exclusive fs resources" hint over to the child across fork(). Acked-by: Jens Axboe <axboe@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] UML Support - Ptrace: adds the host SYSEMU support, for UML and ↵Laurent Vivier2005-09-051-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | general usage Jeff Dike <jdike@addtoit.com>, Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>, Bodo Stroesser <bstroesser@fujitsu-siemens.com> Adds a new ptrace(2) mode, called PTRACE_SYSEMU, resembling PTRACE_SYSCALL except that the kernel does not execute the requested syscall; this is useful to improve performance for virtual environments, like UML, which want to run the syscall on their own. In fact, using PTRACE_SYSCALL means stopping child execution twice, on entry and on exit, and each time you also have two context switches; with SYSEMU you avoid the 2nd stop and so save two context switches per syscall. Also, some architectures don't have support in the host for changing the syscall number via ptrace(), which is currently needed to skip syscall execution (UML turns any syscall into getpid() to avoid it being executed on the host). Fixing that is hard, while SYSEMU is easier to implement. * This version of the patch includes some suggestions of Jeff Dike to avoid adding any instructions to the syscall fast path, plus some other little changes, by myself, to make it work even when the syscall is executed with SYSENTER (but I'm unsure about them). It has been widely tested for quite a lot of time. * Various fixed were included to handle the various switches between various states, i.e. when for instance a syscall entry is traced with one of PT_SYSCALL / _SYSEMU / _SINGLESTEP and another one is used on exit. Basically, this is done by remembering which one of them was used even after the call to ptrace_notify(). * We're combining TIF_SYSCALL_EMU with TIF_SYSCALL_TRACE or TIF_SINGLESTEP to make do_syscall_trace() notice that the current syscall was started with SYSEMU on entry, so that no notification ought to be done in the exit path; this is a bit of a hack, so this problem is solved in another way in next patches. * Also, the effects of the patch: "Ptrace - i386: fix Syscall Audit interaction with singlestep" are cancelled; they are restored back in the last patch of this series. Detailed descriptions of the patches doing this kind of processing follow (but I've already summed everything up). * Fix behaviour when changing interception kind #1. In do_syscall_trace(), we check the status of the TIF_SYSCALL_EMU flag only after doing the debugger notification; but the debugger might have changed the status of this flag because he continued execution with PTRACE_SYSCALL, so this is wrong. This patch fixes it by saving the flag status before calling ptrace_notify(). * Fix behaviour when changing interception kind #2: avoid intercepting syscall on return when using SYSCALL again. A guest process switching from using PTRACE_SYSEMU to PTRACE_SYSCALL crashes. The problem is in arch/i386/kernel/entry.S. The current SYSEMU patch inhibits the syscall-handler to be called, but does not prevent do_syscall_trace() to be called after this for syscall completion interception. The appended patch fixes this. It reuses the flag TIF_SYSCALL_EMU to remember "we come from PTRACE_SYSEMU and now are in PTRACE_SYSCALL", since the flag is unused in the depicted situation. * Fix behaviour when changing interception kind #3: avoid intercepting syscall on return when using SINGLESTEP. When testing 2.6.9 and the skas3.v6 patch, with my latest patch and had problems with singlestepping on UML in SKAS with SYSEMU. It looped receiving SIGTRAPs without moving forward. EIP of the traced process was the same for all SIGTRAPs. What's missing is to handle switching from PTRACE_SYSCALL_EMU to PTRACE_SINGLESTEP in a way very similar to what is done for the change from PTRACE_SYSCALL_EMU to PTRACE_SYSCALL_TRACE. I.e., after calling ptrace(PTRACE_SYSEMU), on the return path, the debugger is notified and then wake ups the process; the syscall is executed (or skipped, when do_syscall_trace() returns 0, i.e. when using PTRACE_SYSEMU), and do_syscall_trace() is called again. Since we are on the return path of a SYSEMU'd syscall, if the wake up is performed through ptrace(PTRACE_SYSCALL), we must still avoid notifying the parent of the syscall exit. Now, this behaviour is extended even to resuming with PTRACE_SINGLESTEP. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lower VM_DONTCOPY total_vmHugh Dickins2005-07-121-1/+3
| | | | | | | | | dup_mmap of a VM_DONTCOPY vma forgot to lower the child's total_vm. (But no way does this account for the recent report of total_vm seen too low.) Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Update cfq io scheduler to time sliced designJens Axboe2005-06-271-0/+5
| | | | | | | | | | | | | | This updates the CFQ io scheduler to the new time sliced design (cfq v3). It provides full process fairness, while giving excellent aggregate system throughput even for many competing processes. It supports io priorities, either inherited from the cpu nice value or set directly with the ioprio_get/set syscalls. The latter closely mimic set/getpriority. This import is based on my latest from -mm. Signed-off-by: Jens Axboe <axboe@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sched: consolidate sbe sbfNick Piggin2005-06-251-9/+12
| | | | | | | | | | | | | | | | Consolidate balance-on-exec with balance-on-fork. This is made easy by the sched-domains RCU patches. As well as the general goodness of code reduction, this allows the runqueues to be unlocked during balance-on-fork. schedstats is a problem. Maybe just have balance-on-event instead of distinguishing fork and exec? Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] dup_mmap: update comment on new vmaHugh Dickins2005-06-211-2/+3
| | | | | | | | | | Remove part of comment on linking new vma in dup_mmap: since anon_vma rmap came in, try_to_unmap_one knows the vma without needing find_vma. But add a comment to note that here vma is inserted without mmap_sem. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Avoiding mmap fragmentationWolfgang Wander2005-06-211-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ingo recently introduced a great speedup for allocating new mmaps using the free_area_cache pointer which boosts the specweb SSL benchmark by 4-5% and causes huge performance increases in thread creation. The downside of this patch is that it does lead to fragmentation in the mmap-ed areas (visible via /proc/self/maps), such that some applications that work fine under 2.4 kernels quickly run out of memory on any 2.6 kernel. The problem is twofold: 1) the free_area_cache is used to continue a search for memory where the last search ended. Before the change new areas were always searched from the base address on. So now new small areas are cluttering holes of all sizes throughout the whole mmap-able region whereas before small holes tended to close holes near the base leaving holes far from the base large and available for larger requests. 2) the free_area_cache also is set to the location of the last munmap-ed area so in scenarios where we allocate e.g. five regions of 1K each, then free regions 4 2 3 in this order the next request for 1K will be placed in the position of the old region 3, whereas before we appended it to the still active region 1, placing it at the location of the old region 2. Before we had 1 free region of 2K, now we only get two free regions of 1K -> fragmentation. The patch addresses thes issues by introducing yet another cache descriptor cached_hole_size that contains the largest known hole size below the current free_area_cache. If a new request comes in the size is compared against the cached_hole_size and if the request can be filled with a hole below free_area_cache the search is started from the base instead. The results look promising: Whereas 2.6.12-rc4 fragments quickly and my (earlier posted) leakme.c test program terminates after 50000+ iterations with 96 distinct and fragmented maps in /proc/self/maps it performs nicely (as expected) with thread creation, Ingo's test_str02 with 20000 threads requires 0.7s system time. Taking out Ingo's patch (un-patch available per request) by basically deleting all mentions of free_area_cache from the kernel and starting the search for new memory always at the respective bases we observe: leakme terminates successfully with 11 distinctive hardly fragmented areas in /proc/self/maps but thread creating is gringdingly slow: 30+s(!) system time for Ingo's test_str02 with 20000 threads. Now - drumroll ;-) the appended patch works fine with leakme: it ends with only 7 distinct areas in /proc/self/maps and also thread creation seems sufficiently fast with 0.71s for 20000 threads. Signed-off-by: Wolfgang Wander <wwc@rentec.com> Credit-to: "Richard Purdie" <rpurdie@rpsys.net> Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> (partly) Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2Linus Torvalds2005-04-161-0/+1274
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!
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