- 02 Oct, 2006 4 commits
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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:
Eric W. Biederman <ebiederm@xmission.com> Acked-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:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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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 36 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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Haavard Skinnemoen authored
Convert m32r to use generic ioremap_page_range() Signed-off-by:
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Haavard Skinnemoen authored
Convert i386 to use generic ioremap_page_range() [bunk@stusta.de: build fix] Signed-off-by:
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Haavard Skinnemoen authored
Convert CRIS to use generic ioremap_page_range() Signed-off-by:
Mikael Starvik <starvik@axis.com> Signed-off-by:
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Haavard Skinnemoen authored
Convert AVR32 to use generic ioremap_page_range() Signed-off-by:
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Haavard Skinnemoen authored
Convert Alpha to use generic ioremap_page_range() by turning __alpha_remap_area_pages() into an inline wrapper around ioremap_page_range(). Signed-off-by:
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Haavard Skinnemoen authored
The existing implementation of ioremap_page_range(), which was taken from i386, does this: flush_cache_all(); /* modify page tables */ flush_tlb_all(); I think this is a bit defensive, so this patch changes the generic implementation to do: /* modify page tables */ flush_cache_vmap(start, end); instead, which is similar to what vmalloc() does. This should still be correct because we never modify existing PTEs. According to James Bottomley: The problem the flush_tlb_all() is trying to solve is to avoid stale tlb entries in the ioremap area. We're just being conservative by flushing on both map and unmap. Technically what vmalloc/vfree does (only flush the tlb on unmap) is just fine because it means that the only tlb entries in the remap area must belong to in-use mappings. Signed-off-by:
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Haavard Skinnemoen authored
This patch adds a generic implementation of ioremap_page_range() in lib/ioremap.c based on the i386 implementation. It differs from the i386 version in the following ways: * The PTE flags are passed as a pgprot_t argument and must be determined up front by the arch-specific code. No additional PTE flags are added. * Uses set_pte_at() instead of set_pte() [bunk@stusta.de: warning fix] ]dhowells@redhat.com: nommu build fix] Signed-off-by:Adrian Bunk <bunk@stusta.de> Signed-off-by:
David Howells <dhowells@redhat.com> Signed-off-by:
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Fernando Vazquez authored
Re-implement smp_send_nmi_allbutself() so that calls to smp_processor_id (through send_IPI_allbutself) can be replaced with safe_smp_processor_id without affecting other parts of the kernel (as suggested by Eric Biederman). Signed-off-by:
Fernando Vazquez <fernando@intellilink.co.jp> Looks-reasonable-to: Andi Kleen <ak@muc.de> Acked-by:
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Fernando Vazquez authored
Substitute "smp_processor_id" with the stack overflow-safe "safe_smp_processor_id" in the reboot path to the second kernel. [akpm@osdl.org: build fix] Signed-off-by:
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Fernando Vazquez authored
"safe_smp_processor_id" implementation for i386-Voyager. Signed-off-by:
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