- 02 Oct, 2006 14 commits
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Eric W. Biederman authored
I took a good hard look at the locking and it appears the locking on vt_pid is the console semaphore. Every modified path is called under the console semaphore except reset_vc when it is called from fn_SAK or do_SAK both of which appear to be in interrupt context. In addition I need to be careful because in the presence of an oops the console_sem may be arbitrarily dropped. Which leads me to conclude the current locking is inadequate for my needs. Given the weird cases we could hit because of oops printing instead of introducing an extra spin lock to protect the data and keep the pid to signal and the signal to send in sync, I have opted to use xchg on just the struct pid * pointer instead. Due to console_sem we will stay in sync between vt_pid and vt_mode except for a small window during a SAK, or oops handling. SAK handling should kill any user space process that care, and oops handling we are broken anyway. Besides the worst that can happen is that I try to send the wrong signal. Signed-off-by:
Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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Eric W. Biederman authored
This is such a rare path it took me a while to figure out how to test this after soring out the locking. This patch does several things. - The variables used are moved into a structure and declared in vt_kern.h - A spinlock is added so we don't have SMP races updating the values. - Instead of raw pid_t value a struct_pid is used to guard against pid wrap around issues, if the daemon to spawn a new console dies. Signed-off-by:
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Eric W. Biederman authored
As we stop storing pid_t's and move to storing struct pid *. We need a way to get the pid_t from the struct pid to report to user space what we have stored. Having a clean well defined way to do this is especially important as we move to multiple pid spaces as may need to report a different value to the caller depending on which pid space the caller is in. Signed-off-by:
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Eric W. Biederman authored
pids aren't something that drivers should care about. However there are a lot of helper layers in the kernel that do care, and are built as modules. Before I can convert them to using struct pid instead of pid_t I need to export the appropriate symbols so they can continue to be built. Signed-off-by:
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Eric W. Biederman authored
Currently the signal functions all either take a task or a pid_t argument. This patch implements variants that take a struct pid *. After all of the users have been update it is my intention to remove the variants that take a pid_t as using pid_t can be more work (an extra hash table lookup) and difficult to get right in the presence of multiple pid namespaces. There are two kinds of functions introduced in this patch. The are the general use functions kill_pgrp and kill_pid which take a priv argument that is ultimately used to create the appropriate siginfo information, Then there are _kill_pgrp_info, kill_pgrp_info, kill_pid_info the internal implementation helpers that take an explicit siginfo. The distinction is made because filling out an explcit siginfo is tricky, and will be even more tricky when pid namespaces are introduced. Signed-off-by:
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Eric W. Biederman authored
To avoid pid rollover confusion the kernel needs to work with struct pid * instead of pid_t. Currently there is not an iterator that walks through all of the tasks of a given pid type starting with a struct pid. This prevents us replacing some pid_t instances with struct pid. So this patch adds do_each_pid_task which walks through the set of task for a given pid type starting with a struct pid. Signed-off-by:
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Eric W. Biederman authored
In the last round of cleaning up the pid hash table a more general struct pid was introduced, that can be referenced counted. With the more general struct pid most if not all places where we store a pid_t we can now store a struct pid * and remove the need for a hash table lookup, and avoid any possible problems with pid roll over. Looking forward to the pid namespaces struct pid * gives us an absolute form a pid so we can compare and use them without caring which pid namespace we are in. This patchset introduces the infrastructure needed to use struct pid instead of pid_t, and then it goes on to convert two different kernel users that currently store a pid_t value. There are a lot more places to go but this is enough to get the basic idea. Before we can merge a pid namespace patch all of the kernel pid_t users need to be examined. Those that deal with user space processes need to be converted to using a struct pid *. Those that deal with kernel processes need to converted to using the kthread api. A rare few that only use their current processes pid values get to be left alone. This patch: task_session returns the struct pid of a tasks session. task_pgrp returns the struct pid of a tasks process group. task_tgid returns the struct pid of a tasks thread group. task_pid returns the struct pid of a tasks process id. These can be used to avoid unnecessary hash table lookups, and to implement safe pid comparisions in the face of a pid namespace. Signed-off-by:
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Eric W. Biederman authored
Helper functions in base.c like proc_pident_readdir and proc_pident_lookup assume the directories have an associated task, and cannot currently be used on the /proc root directory because it does not have such a task. This small changes allows for base.c to be simplified and later when multiple pid spaces are introduced it makes getting the needed context information trivial. Signed-off-by:
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Eric W. Biederman authored
Currently proc_pident_lookup gets the names and types from a table and then has a huge switch statement to get the inode and file operations it needs. That is silly and is becoming increasingly hard to maintain so I just put all of the information in the table. Signed-off-by:
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Eric W. Biederman authored
There were enough changes in my last round of cleaning up proc I had to break up the patch series into smaller chunks, and my last chunk never got resent. This patchset gives proc dynamic inode numbers (the static inode numbers were a pain to maintain and prevent all kinds of things), and removes the horrible switch statements that had to be kept in sync with everything else. Being fully table driver takes us 90% of the way of being able to register new process specific attributes in proc. This patch: Group the functions by what they implement instead of by type of operation. As it existed base.c was quickly approaching the point where it could not be followed. No functionality or code changes asside from adding/removing forward declartions are implemented in this patch. Signed-off-by:
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Eric W. Biederman authored
The problem: An opendir, readdir, closedir sequence can fail to report process ids that are continually in use throughout the sequence of system calls. For this race to trigger the process that proc_pid_readdir stops at must exit before readdir is called again. This can cause ps to fail to report processes, and it is in violation of posix guarantees and normal application expectations with respect to readdir. Currently there is no way to work around this problem in user space short of providing a gargantuan buffer to user space so the directory read all happens in on system call. This patch implements the normal directory semantics for proc, that guarantee that a directory entry that is neither created nor destroyed while reading the directory entry will be returned. For directory that are either created or destroyed during the readdir you may or may not see them. Furthermore you may seek to a directory offset you have previously seen. These are the guarantee that ext[23] provides and that posix requires, and more importantly that user space expects. Plus it is a simple semantic to implement reliable service. It is just a matter of calling readdir a second time if you are wondering if something new has show up. These better semantics are implemented by scanning through the pids in numerical order and by making the file offset a pid plus a fixed offset. The pid scan happens on the pid bitmap, which when you look at it is remarkably efficient for a brute force algorithm. Given that a typical cache line is 64 bytes and thus covers space for 64*8 == 200 pids. There are only 40 cache lines for the entire 32K pid space. A typical system will have 100 pids or more so this is actually fewer cache lines we have to look at to scan a linked list, and the worst case of having to scan the entire pid bitmap is pretty reasonable. If we need something more efficient we can go to a more efficient data structure for indexing the pids, but for now what we have should be sufficient. In addition this takes no additional locks and is actually less code than what we are doing now. Also another very subtle bug in this area has been fixed. It is possible to catch a task in the middle of de_thread where a thread is assuming the thread of it's thread group leader. This patch carefully handles that case so if we hit it we don't fail to return the pid, that is undergoing the de_thread dance. Thanks to KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> for providing the first fix, pointing this out and working on it. [oleg@tv-sign.ru: fix it] Signed-off-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by:
Oleg Nesterov <oleg@tv-sign.ru> Cc: Jean Delvare <jdelvare@suse.de> Signed-off-by:
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Randy Dunlap authored
When listing loaded modules during an oops or panic, also list each module's Tainted flags if non-zero (P: Proprietary or F: Forced load only). If a module is did not taint the kernel, it is just listed like usbcore but if it did taint the kernel, it is listed like wizmodem(PF) Example: [ 3260.121718] Unable to handle kernel NULL pointer dereference at 0000000000000000 RIP: [ 3260.121729] [<ffffffff8804c099>] :dump_test:proc_dump_test+0x99/0xc8 [ 3260.121742] PGD fe8d067 PUD 264a6067 PMD 0 [ 3260.121748] Oops: 0002 [1] SMP [ 3260.121753] CPU 1 [ 3260.121756] Modules linked in: dump_test(P) snd_pcm_oss snd_mixer_oss snd_seq snd_seq_device ide_cd generic ohci1394 snd_hda_intel snd_hda_codec snd_pcm snd_timer snd ieee1394 snd_page_alloc piix ide_core arcmsr aic79xx scsi_transport_spi usblp [ 3260.121785] Pid: 5556, comm: bash Tainted: P 2.6.18-git10 #1 [Alternatively, I can look into listing tainted flags with 'lsmod', but that won't help in oopsen/panics so much.] [akpm@osdl.org: cleanup] Signed-off-by:
Randy Dunlap <rdunlap@xenotime.net> Signed-off-by:
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Dean Nelson authored
The exported kernel interfaces of genpool allocator need to adhere to the requirements of kernel-doc. Signed-off-by:
Dean Nelson <dcn@sgi.com> Cc: Steve Wise <swise@opengridcomputing.com> Acked-by:
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Steve Wise authored
Modules using the genpool allocator need to be able to destroy the data structure when unloading. Signed-off-by:
Steve Wise <swise@opengridcomputing.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Dean Nelson <dcn@sgi.com> Signed-off-by:
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- 01 Oct, 2006 26 commits
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Linus Torvalds authored
The test for the error from pcmcia_replace_cis() was incorrect, and would always trigger (because if an error didn't happen, the "ret" value would not be zero, it would be the passed-in count). Reported and debugged by Fabrice Bellet <fabrice@bellet.info> Rather than just fix the single broken test, make the code in question use an understandable code-sequence instead, fixing the whole function to be more readable. Signed-off-by: -
Andrew Morton authored
It's not clear how this thinko got through.. Cc: Olaf Hering <olaf@aepfle.de> Cc: David Brownell <david-b@pacbell.net> Cc: Alessandro Zummo <alessandro.zummo@towertech.it> Signed-off-by:
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Linus Torvalds authored
* master.kernel.org:/pub/scm/linux/kernel/git/davej/agpgart: [AGPGART] printk fixups. [AGPGART] Use pci_get_slot not pci_find_slot
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Linus Torvalds authored
* master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq: [CPUFREQ] Make acpi-cpufreq unsticky again. [CPUFREQ] longhaul: remove duplicated code. [CPUFREQ] Longhaul - Disable arbiter CLE266 [CPUFREQ] Fix section mismatch warning [CPUFREQ] Fix cut-n-paste bug in suspend printk
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Zachary Amsden authored
During tracking down a PAE compile failure, I found that config.h was being included in a bunch of places in i386 code. It is no longer necessary, so drop it. Signed-off-by:
Zachary Amsden <zach@vmware.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by:
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Zachary Amsden authored
Add a pte_update_hook which notifies about pte changes that have been made without using the set_pte / clear_pte interfaces. This allows shadow mode hypervisors which do not trap on page table access to maintain synchronized shadows. It also turns out, there was one pte update in PAE mode that wasn't using any accessor interface at all for setting NX protection. Considering it is PAE specific, and the accessor is i386 specific, I didn't want to add a generic encapsulation of this behavior yet. Signed-off-by:
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Zachary Amsden authored
Now that ptep_establish has a definition in PAE i386 3-level paging code, the only paging model which is insane enough to have multi-word hardware PTEs which are not efficient to set atomically, we can remove the ghost of set_pte_atomic from other architectures which falesly duplicated it, and remove all knowledge of it from the generic pgtable code. set_pte_atomic is now a private pte operator which is specific to i386 Signed-off-by:
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Zachary Amsden authored
The ptep_establish macro is only used on user-level PTEs, for P->P mapping changes. Since these always happen under protection of the pagetable lock, the strong synchronization of a 64-bit cmpxchg is not needed, in fact, not even a lock prefix needs to be used. We can simply instead clear the P-bit, followed by a normal set. The write ordering is still important to avoid the possibility of the TLB snooping a partially written PTE and getting a bad mapping installed. Signed-off-by:
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Zachary Amsden authored
Create a new PTE function which combines clearing a kernel PTE with the subsequent flush. This allows the two to be easily combined into a single hypercall or paravirt-op. More subtly, reverse the order of the flush for kmap_atomic. Instead of flushing on establishing a mapping, flush on clearing a mapping. This eliminates the possibility of leaving stale kmap entries which may still have valid TLB mappings. This is required for direct mode hypervisors, which need to reprotect all mappings of a given page when changing the page type from a normal page to a protected page (such as a page table or descriptor table page). But it also provides some nicer semantics for real hardware, by providing extra debug-proofing against using stale mappings, as well as ensuring that no stale mappings exist when changing the cacheability attributes of a page, which could lead to cache conflicts when two different types of mappings exist for the same page. Signed-off-by:
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Zachary Amsden authored
Remove ptep_test_and_clear_{dirty|young} from i386, and instead use the dominating functions, ptep_clear_flush_{dirty|young}. This allows the TLB page flush to be contained in the same macro, and allows for an eager optimization - if reading the PTE initially returned dirty/accessed, we can assume the fact that no subsequent update to the PTE which cleared accessed / dirty has occurred, as the only way A/D bits can change without holding the page table lock is if a remote processor clears them. This eliminates an extra branch which came from the generic version of the code, as we know that no other CPU could have cleared the A/D bit, so the flush will always be needed. We still export these two defines, even though we do not actually define the macros in the i386 code: #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY The reason for this is that the only use of these functions is within the generic clear_flush functions, and we want a strong guarantee that there are no other users of these functions, so we want to prevent the generic code from defining them for us. Signed-off-by: -
Zachary Amsden authored
Implement lazy MMU update hooks which are SMP safe for both direct and shadow page tables. The idea is that PTE updates and page invalidations while in lazy mode can be batched into a single hypercall. We use this in VMI for shadow page table synchronization, and it is a win. It also can be used by PPC and for direct page tables on Xen. For SMP, the enter / leave must happen under protection of the page table locks for page tables which are being modified. This is because otherwise, you end up with stale state in the batched hypercall, which other CPUs can race ahead of. Doing this under the protection of the locks guarantees the synchronization is correct, and also means that spurious faults which are generated during this window by remote CPUs are properly handled, as the page fault handler must re-check the PTE under protection of the same lock. Signed-off-by:
Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Signed-off-by:
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Zachary Amsden authored
Change pte_clear_full to a more appropriately named pte_clear_not_present, allowing optimizations when not-present mapping changes need not be reflected in the hardware TLB for protected page table modes. There is also another case that can use it in the fremap code. Signed-off-by:
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Zachary Amsden authored
We don't want to read PTEs directly like this after they have been modified, as a lazy MMU implementation of direct page tables may not have written the updated PTE back to memory yet. Signed-off-by:
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Andrew Morton authored
The recent fix to invalidate_inode_pages() (git commit 016eb4a0) managed to unfix invalidate_inode_pages2(). The problem is that various bits of code in the kernel can take transient refs on pages: the page scanner will do this when inspecting a batch of pages, and the lru_cache_add() batching pagevecs also hold a ref. Net result is transient failures in invalidate_inode_pages2(). This affects NFS directory invalidation (observed) and presumably also block-backed direct-io (not yet reported). Fix it by reverting invalidate_inode_pages2() back to the old version which ignores the page refcounts. We may come up with something more clever later, but for now we need a 2.6.18 fix for NFS. Cc: Chuck Lever <cel@citi.umich.edu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@kernel.org> Signed-off-by:
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Andi Kleen authored
Using the infrastructure created in previous patches implement support to pipe core dumps into programs. This is done by overloading the existing core_pattern sysctl with a new syntax: |program When the first character of the pattern is a '|' the kernel will instead threat the rest of the pattern as a command to run. The core dump will be written to the standard input of that program instead of to a file. This is useful for having automatic core dump analysis without filling up disks. The program can do some simple analysis and save only a summary of the core dump. The core dump proces will run with the privileges and in the name space of the process that caused the core dump. I also increased the core pattern size to 128 bytes so that longer command lines fit. Most of the changes comes from allowing core dumps without seeks. They are fairly straight forward though. One small incompatibility is that if someone had a core pattern previously that started with '|' they will get suddenly new behaviour. I think that's unlikely to be a real problem though. Additional background: > Very nice, do you happen to have a program that can accept this kind of > input for crash dumps? I'm guessing that the embedded people will > really want this functionality. I had a cheesy demo/prototype. Basically it wrote the dump to a file again, ran gdb on it to get a backtrace and wrote the summary to a shared directory. Then there was a simple CGI script to generate a "top 10" crashes HTML listing. Unfortunately this still had the disadvantage to needing full disk space for a dump except for deleting it afterwards (in fact it was worse because over the pipe holes didn't work so if you have a holey address map it would require more space). Fortunately gdb seems to be happy to handle /proc/pid/fd/xxx input pipes as cores (at least it worked with zsh's =(cat core) syntax), so it would be likely possible to do it without temporary space with a simple wrapper that calls it in the right way. I ran out of time before doing that though. The demo prototype scripts weren't very good. If there is really interest I can dig them out (they are currently on a laptop disk on the desk with the laptop itself being in service), but I would recommend to rewrite them for any serious application of this and fix the disk space problem. Also to be really useful it should probably find a way to automatically fetch the debuginfos (I cheated and just installed them in advance). If nobody else does it I can probably do the rewrite myself again at some point. My hope at some point was that desktops would support it in their builtin crash reporters, but at least the KDE people I talked too seemed to be happy with their user space only solution. Alan sayeth: I don't believe that piping as such as neccessarily the right model, but the ability to intercept and processes core dumps from user space is asked for by many enterprise users as well. They want to know about, capture, analyse and process core dumps, often centrally and in automated form. [akpm@osdl.org: loff_t != unsigned long] Signed-off-by:
Andi Kleen <ak@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by:
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Andi Kleen authored
A new member in the ever growing family of call_usermode* functions is born. The new call_usermodehelper_pipe() function allows to pipe data to the stdin of the called user mode progam and behaves otherwise like the normal call_usermodehelp() (except that it always waits for the child to finish) Signed-off-by:
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Andi Kleen authored
Split the big and hard to read do_pipe function into smaller pieces. This creates new create_write_pipe/free_write_pipe/create_read_pipe functions. These functions are made global so that they can be used by other parts of the kernel. The resulting code is more generic and easier to read and has cleaner error handling and less gotos. [akpm@osdl.org: cleanup] Signed-off-by:
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Amol Lad authored
ioremap must be balanced by an iounmap and failing to do so can result in a memory leak. Signed-off-by:
Amol Lad <amol@verismonetworks.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: David S. Miller <davem@sunset.davemloft.net> Signed-off-by:
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Amol Lad authored
ioremap must be balanced by an iounmap and failing to do so can result in a memory leak. Signed-off-by:
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Amol Lad authored
ioremap must be balanced by an iounmap and failing to do so can result in a memory leak. Signed-off-by:
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Amol Lad authored
ioremap must be balanced by an iounmap and failing to do so can result in a memory leak. Signed-off-by:
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Amol Lad authored
ioremap must be balanced by an iounmap and failing to do so can result in a memory leak. Signed-off-by:
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Amol Lad authored
ioremap must be balanced by an iounmap and failing to do so can result in a memory leak. Signed-off-by:
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Amol Lad authored
ioremap must be balanced by an iounmap and failing to do so can result in a memory leak. Signed-off-by:
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Amol Lad authored
ioremap must be balanced by an iounmap and failing to do so can result in a memory leak. Signed-off-by:
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Haavard Skinnemoen authored
Convert x86_64 to use generic ioremap_page_range() [akpm@osdl.org: build fix] Signed-off-by:
Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by:
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