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* mm: thp: fix pmd_bad() triggering in code paths holding mmap_sem read modeAndrea Arcangeli2012-04-021-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 1a5a9906d4e8d1976b701f889d8f35d54b928f25 upstream. In some cases it may happen that pmd_none_or_clear_bad() is called with the mmap_sem hold in read mode. In those cases the huge page faults can allocate hugepmds under pmd_none_or_clear_bad() and that can trigger a false positive from pmd_bad() that will not like to see a pmd materializing as trans huge. It's not khugepaged causing the problem, khugepaged holds the mmap_sem in write mode (and all those sites must hold the mmap_sem in read mode to prevent pagetables to go away from under them, during code review it seems vm86 mode on 32bit kernels requires that too unless it's restricted to 1 thread per process or UP builds). The race is only with the huge pagefaults that can convert a pmd_none() into a pmd_trans_huge(). Effectively all these pmd_none_or_clear_bad() sites running with mmap_sem in read mode are somewhat speculative with the page faults, and the result is always undefined when they run simultaneously. This is probably why it wasn't common to run into this. For example if the madvise(MADV_DONTNEED) runs zap_page_range() shortly before the page fault, the hugepage will not be zapped, if the page fault runs first it will be zapped. Altering pmd_bad() not to error out if it finds hugepmds won't be enough to fix this, because zap_pmd_range would then proceed to call zap_pte_range (which would be incorrect if the pmd become a pmd_trans_huge()). The simplest way to fix this is to read the pmd in the local stack (regardless of what we read, no need of actual CPU barriers, only compiler barrier needed), and be sure it is not changing under the code that computes its value. Even if the real pmd is changing under the value we hold on the stack, we don't care. If we actually end up in zap_pte_range it means the pmd was not none already and it was not huge, and it can't become huge from under us (khugepaged locking explained above). All we need is to enforce that there is no way anymore that in a code path like below, pmd_trans_huge can be false, but pmd_none_or_clear_bad can run into a hugepmd. The overhead of a barrier() is just a compiler tweak and should not be measurable (I only added it for THP builds). I don't exclude different compiler versions may have prevented the race too by caching the value of *pmd on the stack (that hasn't been verified, but it wouldn't be impossible considering pmd_none_or_clear_bad, pmd_bad, pmd_trans_huge, pmd_none are all inlines and there's no external function called in between pmd_trans_huge and pmd_none_or_clear_bad). if (pmd_trans_huge(*pmd)) { if (next-addr != HPAGE_PMD_SIZE) { VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem)); split_huge_page_pmd(vma->vm_mm, pmd); } else if (zap_huge_pmd(tlb, vma, pmd, addr)) continue; /* fall through */ } if (pmd_none_or_clear_bad(pmd)) Because this race condition could be exercised without special privileges this was reported in CVE-2012-1179. The race was identified and fully explained by Ulrich who debugged it. I'm quoting his accurate explanation below, for reference. ====== start quote ======= mapcount 0 page_mapcount 1 kernel BUG at mm/huge_memory.c:1384! At some point prior to the panic, a "bad pmd ..." message similar to the following is logged on the console: mm/memory.c:145: bad pmd ffff8800376e1f98(80000000314000e7). The "bad pmd ..." message is logged by pmd_clear_bad() before it clears the page's PMD table entry. 143 void pmd_clear_bad(pmd_t *pmd) 144 { -> 145 pmd_ERROR(*pmd); 146 pmd_clear(pmd); 147 } After the PMD table entry has been cleared, there is an inconsistency between the actual number of PMD table entries that are mapping the page and the page's map count (_mapcount field in struct page). When the page is subsequently reclaimed, __split_huge_page() detects this inconsistency. 1381 if (mapcount != page_mapcount(page)) 1382 printk(KERN_ERR "mapcount %d page_mapcount %d\n", 1383 mapcount, page_mapcount(page)); -> 1384 BUG_ON(mapcount != page_mapcount(page)); The root cause of the problem is a race of two threads in a multithreaded process. Thread B incurs a page fault on a virtual address that has never been accessed (PMD entry is zero) while Thread A is executing an madvise() system call on a virtual address within the same 2 MB (huge page) range. virtual address space .---------------------. | | | | .-|---------------------| | | | | | |<-- B(fault) | | | 2 MB | |/////////////////////|-. huge < |/////////////////////| > A(range) page | |/////////////////////|-' | | | | | | '-|---------------------| | | | | '---------------------' - Thread A is executing an madvise(..., MADV_DONTNEED) system call on the virtual address range "A(range)" shown in the picture. sys_madvise // Acquire the semaphore in shared mode. down_read(&current->mm->mmap_sem) ... madvise_vma switch (behavior) case MADV_DONTNEED: madvise_dontneed zap_page_range unmap_vmas unmap_page_range zap_pud_range zap_pmd_range // // Assume that this huge page has never been accessed. // I.e. content of the PMD entry is zero (not mapped). // if (pmd_trans_huge(*pmd)) { // We don't get here due to the above assumption. } // // Assume that Thread B incurred a page fault and .---------> // sneaks in here as shown below. | // | if (pmd_none_or_clear_bad(pmd)) | { | if (unlikely(pmd_bad(*pmd))) | pmd_clear_bad | { | pmd_ERROR | // Log "bad pmd ..." message here. | pmd_clear | // Clear the page's PMD entry. | // Thread B incremented the map count | // in page_add_new_anon_rmap(), but | // now the page is no longer mapped | // by a PMD entry (-> inconsistency). | } | } | v - Thread B is handling a page fault on virtual address "B(fault)" shown in the picture. ... do_page_fault __do_page_fault // Acquire the semaphore in shared mode. down_read_trylock(&mm->mmap_sem) ... handle_mm_fault if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) // We get here due to the above assumption (PMD entry is zero). do_huge_pmd_anonymous_page alloc_hugepage_vma // Allocate a new transparent huge page here. ... __do_huge_pmd_anonymous_page ... spin_lock(&mm->page_table_lock) ... page_add_new_anon_rmap // Here we increment the page's map count (starts at -1). atomic_set(&page->_mapcount, 0) set_pmd_at // Here we set the page's PMD entry which will be cleared // when Thread A calls pmd_clear_bad(). ... spin_unlock(&mm->page_table_lock) The mmap_sem does not prevent the race because both threads are acquiring it in shared mode (down_read). Thread B holds the page_table_lock while the page's map count and PMD table entry are updated. However, Thread A does not synchronize on that lock. ====== end quote ======= [akpm@linux-foundation.org: checkpatch fixes] Reported-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Jones <davej@redhat.com> Acked-by: Larry Woodman <lwoodman@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Mark Salter <msalter@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* proc: make sure mem_open() doesn't pin the target's memoryOleg Nesterov2012-02-131-1/+13
| | | | | | | | | | | | | | | | | | | | | | | | commit 6d08f2c7139790c268820a2e590795cb8333181a upstream. Once /proc/pid/mem is opened, the memory can't be released until mem_release() even if its owner exits. Change mem_open() to do atomic_inc(mm_count) + mmput(), this only pins mm_struct. Change mem_rw() to do atomic_inc_not_zero(mm_count) before access_remote_vm(), this verifies that this mm is still alive. I am not sure what should mem_rw() return if atomic_inc_not_zero() fails. With this patch it returns zero to match the "mm == NULL" case, may be it should return -EINVAL like it did before e268337d. Perhaps it makes sense to add the additional fatal_signal_pending() check into the main loop, to ensure we do not hold this memory if the target task was oom-killed. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* proc: unify mem_read() and mem_write()Oleg Nesterov2012-02-131-58/+32
| | | | | | | | | | | | | | | commit 572d34b946bae070debd42db1143034d9687e13f upstream. No functional changes, cleanup and preparation. mem_read() and mem_write() are very similar. Move this code into the new common helper, mem_rw(), which takes the additional "int write" argument. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* proc: mem_release() should check mm != NULLOleg Nesterov2012-02-131-2/+2
| | | | | | | | | | | commit 71879d3cb3dd8f2dfdefb252775c1b3ea04a3dd4 upstream. mem_release() can hit mm == NULL, add the necessary check. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* proc: clear_refs: do not clear reserved pagesWill Deacon2012-01-251-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 85e72aa5384b1a614563ad63257ded0e91d1a620 upstream. /proc/pid/clear_refs is used to clear the Referenced and YOUNG bits for pages and corresponding page table entries of the task with PID pid, which includes any special mappings inserted into the page tables in order to provide things like vDSOs and user helper functions. On ARM this causes a problem because the vectors page is mapped as a global mapping and since ec706dab ("ARM: add a vma entry for the user accessible vector page"), a VMA is also inserted into each task for this page to aid unwinding through signals and syscall restarts. Since the vectors page is required for handling faults, clearing the YOUNG bit (and subsequently writing a faulting pte) means that we lose the vectors page *globally* and cannot fault it back in. This results in a system deadlock on the next exception. To see this problem in action, just run: $ echo 1 > /proc/self/clear_refs on an ARM platform (as any user) and watch your system hang. I think this has been the case since 2.6.37 This patch avoids clearing the aforementioned bits for reserved pages, therefore leaving the vectors page intact on ARM. Since reserved pages are not candidates for swap, this change should not have any impact on the usefulness of clear_refs. Signed-off-by: Will Deacon <will.deacon@arm.com> Reported-by: Moussa Ba <moussaba@micron.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Russell King <rmk@arm.linux.org.uk> Acked-by: Nicolas Pitre <nico@linaro.org> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* proc: clean up and fix /proc/<pid>/mem handlingLinus Torvalds2012-01-251-106/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit e268337dfe26dfc7efd422a804dbb27977a3cccc upstream. Jüri Aedla reported that the /proc/<pid>/mem handling really isn't very robust, and it also doesn't match the permission checking of any of the other related files. This changes it to do the permission checks at open time, and instead of tracking the process, it tracks the VM at the time of the open. That simplifies the code a lot, but does mean that if you hold the file descriptor open over an execve(), you'll continue to read from the _old_ VM. That is different from our previous behavior, but much simpler. If somebody actually finds a load where this matters, we'll need to revert this commit. I suspect that nobody will ever notice - because the process mapping addresses will also have changed as part of the execve. So you cannot actually usefully access the fd across a VM change simply because all the offsets for IO would have changed too. Reported-by: Jüri Aedla <asd@ut.ee> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* fix cputime overflow in uptime_proc_showMartin Schwidefsky2012-01-251-2/+7
| | | | | | | | | | | | | | commit c3e0ef9a298e028a82ada28101ccd5cf64d209ee upstream. For 32-bit architectures using standard jiffies the idletime calculation in uptime_proc_show will quickly overflow. It takes (2^32 / HZ) seconds of idle-time, or e.g. 12.45 days with no load on a quad-core with HZ=1000. Switch to 64-bit calculations. Cc: Michael Abbott <michael.abbott@diamond.ac.uk> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* fs/proc/meminfo.c: fix compilation errorClaudio Scordino2011-12-211-3/+4
| | | | | | | | | | | | | | commit b53fc7c2974a50913f49e1d800fe904a28c338e3 upstream. Fix the error message "directives may not be used inside a macro argument" which appears when the kernel is compiled for the cris architecture. Signed-off-by: Claudio Scordino <claudio@evidence.eu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* vfs: show O_CLOEXE bit properly in /proc/<pid>/fdinfo/<fd> filesLinus Torvalds2011-11-111-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | commit 1117f72ea0217ba0cc19f05adbbd8b9a397f5ab7 upstream. The CLOEXE bit is magical, and for performance (and semantic) reasons we don't actually maintain it in the file descriptor itself, but in a separate bit array. Which means that when we show f_flags, the CLOEXE status is shown incorrectly: we show the status not as it is now, but as it was when the file was opened. Fix that by looking up the bit properly in the 'fdt->close_on_exec' bit array. Uli needs this in order to re-implement the pfiles program: "For normal file descriptors (not sockets) this was the last piece of information which wasn't available. This is all part of my 'give Solaris users no reason to not switch' effort. I intend to offer the code to the util-linux-ng maintainers." Requested-by: Ulrich Drepper <drepper@akkadia.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* /proc/self/numa_maps: restore "huge" tag for hugetlb vmasAndrew Morton2011-11-111-0/+3
| | | | | | | | | | | | | | | | | | | | | commit fc360bd9cdcf875639a77f07fafec26699c546f3 upstream. The display of the "huge" tag was accidentally removed in 29ea2f698 ("mm: use walk_page_range() instead of custom page table walking code"). Reported-by: Stephen Hemminger <shemminger@vyatta.com> Tested-by: Stephen Hemminger <shemminger@vyatta.com> Reviewed-by: Stephen Wilson <wilsons@start.ca> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* teach /proc/$pid/numa_maps about transparent hugepagesDave Hansen2011-10-031-0/+20
| | | | | | | | | | | | | | | | | | commit 32ef43848f283e0ef945d3c67e851c143fea3970 upstream. This is modeled after the smaps code. It detects transparent hugepages and then does a single gather_stats() for the page as a whole. This has two benifits: 1. It is more efficient since it does many pages in a single shot. 2. It does not have to break down the huge page. Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* break out numa_maps gather_pte_stats() checksDave Hansen2011-10-031-15/+24
| | | | | | | | | | | | | | | | | | commit 3200a8aaab0c9ccdc0f59b0dac2d4a47029137fa upstream. gather_pte_stats() does a number of checks on a target page to see whether it should even be considered for statistics. This breaks that code out in to a separate function so that we can use it in the transparent hugepage case in the next patch. Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Acked-by: Hugh Dickins <hughd@google.com> Reviewed-by: Christoph Lameter <cl@gentwo.org> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* make /proc/$pid/numa_maps gather_stats() take variable page sizeDave Hansen2011-10-031-10/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit eb4866d0066ffd5446751c102d64feb3318d8bd1 upstream. We need to teach the numa_maps code about transparent huge pages. The first step is to teach gather_stats() that the pte it is dealing with might represent more than one page. Note that will we use this in a moment for transparent huge pages since they have use a single pmd_t which _acts_ as a "surrogate" for a bunch of smaller pte_t's. I'm a _bit_ unhappy that this interface counts in hugetlbfs page sizes for hugetlbfs pages and PAGE_SIZE for normal pages. That means that to figure out how many _bytes_ "dirty=1" means, you must first know the hugetlbfs page size. That's easier said than done especially if you don't have visibility in to the mount. But, that's probably a discussion for another day especially since it would change behavior to fix it. But, just in case anyone wonders why this patch only passes a '1' in the hugetlb case... Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* proc: fix a race in do_io_accounting()Vasiliy Kulikov2011-08-041-3/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 293eb1e7772b25a93647c798c7b89bf26c2da2e0 upstream. If an inode's mode permits opening /proc/PID/io and the resulting file descriptor is kept across execve() of a setuid or similar binary, the ptrace_may_access() check tries to prevent using this fd against the task with escalated privileges. Unfortunately, there is a race in the check against execve(). If execve() is processed after the ptrace check, but before the actual io information gathering, io statistics will be gathered from the privileged process. At least in theory this might lead to gathering sensible information (like ssh/ftp password length) that wouldn't be available otherwise. Holding task->signal->cred_guard_mutex while gathering the io information should protect against the race. The order of locking is similar to the one inside of ptrace_attach(): first goes cred_guard_mutex, then lock_task_sighand(). Signed-off-by: Vasiliy Kulikov <segoon@openwall.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* proc: restrict access to /proc/PID/ioVasiliy Kulikov2011-06-281-2/+5
| | | | | | | | | | | | | | /proc/PID/io may be used for gathering private information. E.g. for openssh and vsftpd daemons wchars/rchars may be used to learn the precise password length. Restrict it to processes being able to ptrace the target process. ptrace_may_access() is needed to prevent keeping open file descriptor of "io" file, executing setuid binary and gathering io information of the setuid'ed process. Signed-off-by: Vasiliy Kulikov <segoon@openwall.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc_sys_permission() is OK in RCU modeAl Viro2011-06-201-3/+0
| | | | | | | | nothing blocking there, since all instances of sysctl ->permissions() method are non-blocking - both of them, that is. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* proc_fd_permission() is doesn't need to bail out in RCU modeAl Viro2011-06-201-5/+1
| | | | | | nothing blocking except generic_permission() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-2.6-nsfdLinus Torvalds2011-06-161-3/+6
|\ | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-2.6-nsfd: proc: Fix Oops on stat of /proc/<zombie pid>/ns/net
| * proc: Fix Oops on stat of /proc/<zombie pid>/ns/netEric W. Biederman2011-06-151-3/+6
| | | | | | | | | | | | | | | | | | | | Don't call iput with the inode half setup to be a namespace filedescriptor. Instead rearrange the code so that we don't initialize ei->ns_ops until after I ns_ops->get succeeds, preventing us from invoking ns_ops->put when ns_ops->get failed. Reported-by: Ingo Saitz <Ingo.Saitz@stud.uni-hannover.de> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* | fix leak in proc_set_super()Al Viro2011-06-121-5/+6
|/ | | | | | set_anon_super() can fail... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tileLinus Torvalds2011-05-291-0/+9
|\ | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: arch/tile: more /proc and /sys file support
| * arch/tile: more /proc and /sys file supportChris Metcalf2011-05-271-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This change introduces a few of the less controversial /proc and /proc/sys interfaces for tile, along with sysfs attributes for various things that were originally proposed as /proc/tile files. It also adjusts the "hardwall" proc API. Arnd Bergmann reviewed the initial arch/tile submission, which included a complete set of all the /proc/tile and /proc/sys/tile knobs that we had added in a somewhat ad hoc way during initial development, and provided feedback on where most of them should go. One knob turned out to be similar enough to the existing /proc/sys/debug/exception-trace that it was re-implemented to use that model instead. Another knob was /proc/tile/grid, which reported the "grid" dimensions of a tile chip (e.g. 8x8 processors = 64-core chip). Arnd suggested looking at sysfs for that, so this change moves that information to a pair of sysfs attributes (chip_width and chip_height) in the /sys/devices/system/cpu directory. We also put the "chip_serial" and "chip_revision" information from our old /proc/tile/board file as attributes in /sys/devices/system/cpu. Other information collected via hypervisor APIs is now placed in /sys/hypervisor. We create a /sys/hypervisor/type file (holding the constant string "tilera") to be parallel with the Xen use of /sys/hypervisor/type holding "xen". We create three top-level files, "version" (the hypervisor's own version), "config_version" (the version of the configuration file), and "hvconfig" (the contents of the configuration file). The remaining information from our old /proc/tile/board and /proc/tile/switch files becomes an attribute group appearing under /sys/hypervisor/board/. Finally, after some feedback from Arnd Bergmann for the previous version of this patch, the /proc/tile/hardwall file is split up into two conceptual parts. First, a directory /proc/tile/hardwall/ which contains one file per active hardwall, each file named after the hardwall's ID and holding a cpulist that says which cpus are enclosed by the hardwall. Second, a /proc/PID file "hardwall" that is either empty (for non-hardwall-using processes) or contains the hardwall ID. Finally, this change pushes the /proc/sys/tile/unaligned_fixup/ directory, with knobs controlling the kernel code for handling the fixup of unaligned exceptions. Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
* | fs/proc/vmcore.c: add hook to read_from_oldmem() to check for non-ram pagesOlaf Hering2011-05-261-3/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The balloon driver in a Xen guest frees guest pages and marks them as mmio. When the kernel crashes and the crash kernel attempts to read the oldmem via /proc/vmcore a read from ballooned pages will generate 100% load in dom0 because Xen asks qemu-dm for the page content. Since the reads come in as 8byte requests each ballooned page is tried 512 times. With this change a hook can be registered which checks wether the given pfn is really ram. The hook has to return a value > 0 for ram pages, a value < 0 on error (because the hypercall is not known) and 0 for non-ram pages. This will reduce the time to read /proc/vmcore. Without this change a 512M guest with 128M crashkernel region needs 200 seconds to read it, with this change it takes just 2 seconds. Signed-off-by: Olaf Hering <olaf@aepfle.de> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | proc: fix pagemap_read() error caseKOSAKI Motohiro2011-05-261-10/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, pagemap_read() has three error and/or corner case handling mistake. (1) If ppos parameter is wrong, mm refcount will be leak. (2) If count parameter is 0, mm refcount will be leak too. (3) If the current task is sleeping in kmalloc() and the system is out of memory and oom-killer kill the proc associated task, mm_refcount prevent the task free its memory. then system may hang up. <Quote Hugh's explain why we shold call kmalloc() before get_mm()> check_mem_permission gets a reference to the mm. If we __get_free_page after check_mem_permission, imagine what happens if the system is out of memory, and the mm we're looking at is selected for killing by the OOM killer: while we wait in __get_free_page for more memory, no memory is freed from the selected mm because it cannot reach exit_mmap while we hold that reference. This patch fixes the above three. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jovi Zhang <bookjovi@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Stephen Wilson <wilsons@start.ca> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | proc: put check_mem_permission after __get_free_page in mem_writeKOSAKI Motohiro2011-05-261-7/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It whould be better if put check_mem_permission after __get_free_page in mem_write, to be same as function mem_read. Hugh Dickins explained the reason. check_mem_permission gets a reference to the mm. If we __get_free_page after check_mem_permission, imagine what happens if the system is out of memory, and the mm we're looking at is selected for killing by the OOM killer: while we wait in __get_free_page for more memory, no memory is freed from the selected mm because it cannot reach exit_mmap while we hold that reference. Reported-by: Jovi Zhang <bookjovi@gmail.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Reviewed-by: Stephen Wilson <wilsons@start.ca> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | proc/stat: use defined macro KMALLOC_MAX_SIZEYuanhan Liu2011-05-261-3/+3
| | | | | | | | | | | | | | | | | | | | There is a macro for the max size kmalloc can allocate, so use it instead of a hardcoded number. Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | proc: constify status arrayMike Frysinger2011-05-261-2/+2
| | | | | | | | | | | | | | | | | | No need for this local array to be writable, so mark it const. Signed-off-by: Mike Frysinger <vapier@gentoo.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | fs/proc: convert to kstrtoX()Alexey Dobriyan2011-05-262-11/+13
| | | | | | | | | | | | | | | | Convert fs/proc/ from strict_strto*() to kstrto*() functions. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: extract exe_file handling from procfsJiri Slaby2011-05-261-51/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Setup and cleanup of mm_struct->exe_file is currently done in fs/proc/. This was because exe_file was needed only for /proc/<pid>/exe. Since we will need the exe_file functionality also for core dumps (so core name can contain full binary path), built this functionality always into the kernel. To achieve that move that out of proc FS to the kernel/ where in fact it should belong. By doing that we can make dup_mm_exe_file static. Also we can drop linux/proc_fs.h inclusion in fs/exec.c and kernel/fork.c. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: don't access vm_flags as 'int'KOSAKI Motohiro2011-05-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | The type of vma->vm_flags is 'unsigned long'. Neither 'int' nor 'unsigned int'. This patch fixes such misuse. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> [ Changed to use a typedef - we'll extend it to cover more cases later, since there has been discussion about making it a 64-bit type.. - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-2.6-nsfdLinus Torvalds2011-05-255-11/+233
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-2.6-nsfd: net: fix get_net_ns_by_fd for !CONFIG_NET_NS ns proc: Return -ENOENT for a nonexistent /proc/self/ns/ entry. ns: Declare sys_setns in syscalls.h net: Allow setting the network namespace by fd ns proc: Add support for the ipc namespace ns proc: Add support for the uts namespace ns proc: Add support for the network namespace. ns: Introduce the setns syscall ns: proc files for namespace naming policy.
| * | ns proc: Return -ENOENT for a nonexistent /proc/self/ns/ entry.Eric W. Biederman2011-05-241-0/+1
| | | | | | | | | | | | | | | Spotted-by: Nathan Lynch <ntl@pobox.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * | ns proc: Add support for the ipc namespaceEric W. Biederman2011-05-101-0/+3
| | | | | | | | | | | | | | | Acked-by: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * | ns proc: Add support for the uts namespaceEric W. Biederman2011-05-101-0/+3
| | | | | | | | | | | | | | | Acked-by: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * | ns proc: Add support for the network namespace.Eric W. Biederman2011-05-101-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | Implementing file descriptors for the network namespace is simple and straight forward. Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * | ns: proc files for namespace naming policy.Eric W. Biederman2011-05-105-11/+223
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create files under /proc/<pid>/ns/ to allow controlling the namespaces of a process. This addresses three specific problems that can make namespaces hard to work with. - Namespaces require a dedicated process to pin them in memory. - It is not possible to use a namespace unless you are the child of the original creator. - Namespaces don't have names that userspace can use to talk about them. The namespace files under /proc/<pid>/ns/ can be opened and the file descriptor can be used to talk about a specific namespace, and to keep the specified namespace alive. A namespace can be kept alive by either holding the file descriptor open or bind mounting the file someplace else. aka: mount --bind /proc/self/ns/net /some/filesystem/path mount --bind /proc/self/fd/<N> /some/filesystem/path This allows namespaces to be named with userspace policy. It requires additional support to make use of these filedescriptors and that will be comming in the following patches. Acked-by: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* | | Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds2011-05-251-0/+1
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (89 commits) bonding: documentation and code cleanup for resend_igmp bonding: prevent deadlock on slave store with alb mode (v3) net: hold rtnl again in dump callbacks Add Fujitsu 1000base-SX PCI ID to tg3 bnx2x: protect sequence increment with mutex sch_sfq: fix peek() implementation isdn: netjet - blacklist Digium TDM400P via-velocity: don't annotate MAC registers as packed xen: netfront: hold RTNL when updating features. sctp: fix memory leak of the ASCONF queue when free asoc net: make dev_disable_lro use physical device if passed a vlan dev (v2) net: move is_vlan_dev into public header file (v2) bug.h: Fix build with CONFIG_PRINTK disabled. wireless: fix fatal kernel-doc error + warning in mac80211.h wireless: fix cfg80211.h new kernel-doc warnings iwlagn: dbg_fixed_rate only used when CONFIG_MAC80211_DEBUGFS enabled dst: catch uninitialized metrics be2net: hash key for rss-config cmd not set bridge: initialize fake_rtable metrics net: fix __dst_destroy_metrics_generic() ... Fix up trivial conflicts in drivers/staging/brcm80211/brcmfmac/wl_cfg80211.c
| * \ \ Merge ↵John W. Linville2011-05-241-0/+1
| |\ \ \ | | |_|/ | |/| | | | | | ssh://master.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 into for-davem
| | * | airo: correct proc entry creation interfacesAlexey Dobriyan2011-05-161-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * use proc_mkdir_mode() instead of create_proc_entry(S_IFDIR|...), export proc_mkdir_mode() for that, oh well. * don't supply S_IFREG to proc_create_data(), it's unnecessary Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
* | | | proc: allocate storage for numa_maps statistics onceStephen Wilson2011-05-251-9/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In show_numa_map() we collect statistics into a numa_maps structure. Since the number of NUMA nodes can be very large, this structure is not a candidate for stack allocation. Instead of going thru a kmalloc()+kfree() cycle each time show_numa_map() is invoked, perform the allocation just once when /proc/pid/numa_maps is opened. Performing the allocation when numa_maps is opened, and thus before a reference to the target tasks mm is taken, eliminates a potential stalemate condition in the oom-killer as originally described by Hugh Dickins: ... imagine what happens if the system is out of memory, and the mm we're looking at is selected for killing by the OOM killer: while we wait in __get_free_page for more memory, no memory is freed from the selected mm because it cannot reach exit_mmap while we hold that reference. Signed-off-by: Stephen Wilson <wilsons@start.ca> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | proc: make struct proc_maps_private truly privateStephen Wilson2011-05-251-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that mm/mempolicy.c is no longer implementing /proc/pid/numa_maps there is no need to export struct proc_maps_private to the world. Move it to fs/proc/internal.h instead. Signed-off-by: Stephen Wilson <wilsons@start.ca> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | mm: proc: move show_numa_map() to fs/proc/task_mmu.cStephen Wilson2011-05-251-2/+182
|/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Moving show_numa_map() from mempolicy.c to task_mmu.c solves several issues. - Having the show() operation "miles away" from the corresponding seq_file iteration operations is a maintenance burden. - The need to export ad hoc info like struct proc_maps_private is eliminated. - The implementation of show_numa_map() can be improved in a simple manner by cooperating with the other seq_file operations (start, stop, etc) -- something that would be messy to do without this change. Signed-off-by: Stephen Wilson <wilsons@start.ca> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Don't lock guardpage if the stack is growing upMikulas Patocka2011-05-091-5/+7
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Linux kernel excludes guard page when performing mlock on a VMA with down-growing stack. However, some architectures have up-growing stack and locking the guard page should be excluded in this case too. This patch fixes lvm2 on PA-RISC (and possibly other architectures with up-growing stack). lvm2 calculates number of used pages when locking and when unlocking and reports an internal error if the numbers mismatch. [ Patch changed fairly extensively to also fix /proc/<pid>/maps for the grows-up case, and to move things around a bit to clean it all up and share the infrstructure with the /proc bits. Tested on ia64 that has both grow-up and grow-down segments - Linus ] Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Tested-by: Tony Luck <tony.luck@gmail.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | proc: do proper range check on readdir offsetLinus Torvalds2011-04-181-2/+7
| | | | | | | | | | | | | | | | | | | | Rather than pass in some random truncated offset to the pid-related functions, check that the offset is in range up-front. This is just cleanup, the previous commit fixed the real problem. Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Fix common misspellingsLucas De Marchi2011-03-311-1/+1
|/ | | | | | Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
* proc: fix oops on invalid /proc/<pid>/maps accessLinus Torvalds2011-03-271-1/+2
| | | | | | | | | | | | | | | | | | | When m_start returns an error, the seq_file logic will still call m_stop with that error entry, so we'd better make sure that we check it before using it as a vma. Introduced by commit ec6fd8a4355c ("report errors in /proc/*/*map* sanely"), which replaced NULL with various ERR_PTR() cases. (On ia64, you happen to get a unaligned fault instead of a page fault, since the address used is generally some random error code like -EPERM) Reported-by: Anca Emanuel <anca.emanuel@gmail.com> Reported-by: Tony Luck <tony.luck@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Américo Wang <xiyou.wangcong@gmail.com> Cc: Stephen Wilson <wilsons@start.ca> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2011-03-233-78/+132
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: deal with races in /proc/*/{syscall,stack,personality} proc: enable writing to /proc/pid/mem proc: make check_mem_permission() return an mm_struct on success proc: hold cred_guard_mutex in check_mem_permission() proc: disable mem_write after exec mm: implement access_remote_vm mm: factor out main logic of access_process_vm mm: use mm_struct to resolve gate vma's in __get_user_pages mm: arch: rename in_gate_area_no_task to in_gate_area_no_mm mm: arch: make in_gate_area take an mm_struct instead of a task_struct mm: arch: make get_gate_vma take an mm_struct instead of a task_struct x86: mark associated mm when running a task in 32 bit compatibility mode x86: add context tag to mark mm when running a task in 32-bit compatibility mode auxv: require the target to be tracable (or yourself) close race in /proc/*/environ report errors in /proc/*/*map* sanely pagemap: close races with suid execve make sessionid permissions in /proc/*/task/* match those in /proc/* fix leaks in path_lookupat() Fix up trivial conflicts in fs/proc/base.c
| * deal with races in /proc/*/{syscall,stack,personality}Al Viro2011-03-231-19/+50
| | | | | | | | | | | | | | | | | | | | | | All of those are rw-r--r-- and all are broken for suid - if you open a file before the target does suid-root exec, you'll be still able to access it. For personality it's not a big deal, but for syscall and stack it's a real problem. Fix: check that task is tracable for you at the time of read(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * proc: enable writing to /proc/pid/memStephen Wilson2011-03-231-5/+0
| | | | | | | | | | | | | | | | With recent changes there is no longer a security hazard with writing to /proc/pid/mem. Remove the #ifdef. Signed-off-by: Stephen Wilson <wilsons@start.ca> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * proc: make check_mem_permission() return an mm_struct on successStephen Wilson2011-03-231-24/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | This change allows us to take advantage of access_remote_vm(), which in turn eliminates a security issue with the mem_write() implementation. The previous implementation of mem_write() was insecure since the target task could exec a setuid-root binary between the permission check and the actual write. Holding a reference to the target mm_struct eliminates this vulnerability. Signed-off-by: Stephen Wilson <wilsons@start.ca> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
generated by cgit v1.1 at 2024-12-23 17:11:59 +0000