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2014-12-19Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq core fix from Thomas Gleixner: "A single fix plugging a long standing race between proc/stat and proc/interrupts access and freeing of interrupt descriptors" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq: Prevent proc race against freeing of irq descriptors
2014-12-18fs/proc/meminfo.c: include cma info in proc/meminfoPintu Kumar
This patch include CMA info (CMATotal, CMAFree) in /proc/meminfo. Currently, in a CMA enabled system, if somebody wants to know the total CMA size declared, there is no way to tell, other than the dmesg or /var/log/messages logs. With this patch we are showing the CMA info as part of meminfo, so that it can be determined at any point of time. This will be populated only when CMA is enabled. Below is the sample output from a ARM based device with RAM:512MB and CMA:16MB. MemTotal: 471172 kB MemFree: 111712 kB MemAvailable: 271172 kB . . . CmaTotal: 16384 kB CmaFree: 6144 kB This patch also fix below checkpatch errors that were found during these changes. ERROR: space required after that ',' (ctx:ExV) 199: FILE: fs/proc/meminfo.c:199: + ,atomic_long_read(&num_poisoned_pages) << (PAGE_SHIFT - 10) ^ ERROR: space required after that ',' (ctx:ExV) 202: FILE: fs/proc/meminfo.c:202: + ,K(global_page_state(NR_ANON_TRANSPARENT_HUGEPAGES) * ^ ERROR: space required after that ',' (ctx:ExV) 206: FILE: fs/proc/meminfo.c:206: + ,K(totalcma_pages) ^ total: 3 errors, 0 warnings, 2 checks, 236 lines checked Signed-off-by: Pintu Kumar <pintu.k@samsung.com> Signed-off-by: Vishnu Pratap Singh <vishnu.ps@samsung.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: Rafael Aquini <aquini@redhat.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-17Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull user namespace related fixes from Eric Biederman: "As these are bug fixes almost all of thes changes are marked for backporting to stable. The first change (implicitly adding MNT_NODEV on remount) addresses a regression that was created when security issues with unprivileged remount were closed. I go on to update the remount test to make it easy to detect if this issue reoccurs. Then there are a handful of mount and umount related fixes. Then half of the changes deal with the a recently discovered design bug in the permission checks of gid_map. Unix since the beginning has allowed setting group permissions on files to less than the user and other permissions (aka ---rwx---rwx). As the unix permission checks stop as soon as a group matches, and setgroups allows setting groups that can not later be dropped, results in a situtation where it is possible to legitimately use a group to assign fewer privileges to a process. Which means dropping a group can increase a processes privileges. The fix I have adopted is that gid_map is now no longer writable without privilege unless the new file /proc/self/setgroups has been set to permanently disable setgroups. The bulk of user namespace using applications even the applications using applications using user namespaces without privilege remain unaffected by this change. Unfortunately this ix breaks a couple user space applications, that were relying on the problematic behavior (one of which was tools/selftests/mount/unprivileged-remount-test.c). To hopefully prevent needing a regression fix on top of my security fix I rounded folks who work with the container implementations mostly like to be affected and encouraged them to test the changes. > So far nothing broke on my libvirt-lxc test bed. :-) > Tested with openSUSE 13.2 and libvirt 1.2.9. > Tested-by: Richard Weinberger <richard@nod.at> > Tested on Fedora20 with libvirt 1.2.11, works fine. > Tested-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com> > Ok, thanks - yes, unprivileged lxc is working fine with your kernels. > Just to be sure I was testing the right thing I also tested using > my unprivileged nsexec testcases, and they failed on setgroup/setgid > as now expected, and succeeded there without your patches. > Tested-by: Serge Hallyn <serge.hallyn@ubuntu.com> > I tested this with Sandstorm. It breaks as is and it works if I add > the setgroups thing. > Tested-by: Andy Lutomirski <luto@amacapital.net> # breaks things as designed :(" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: userns: Unbreak the unprivileged remount tests userns; Correct the comment in map_write userns: Allow setting gid_maps without privilege when setgroups is disabled userns: Add a knob to disable setgroups on a per user namespace basis userns: Rename id_map_mutex to userns_state_mutex userns: Only allow the creator of the userns unprivileged mappings userns: Check euid no fsuid when establishing an unprivileged uid mapping userns: Don't allow unprivileged creation of gid mappings userns: Don't allow setgroups until a gid mapping has been setablished userns: Document what the invariant required for safe unprivileged mappings. groups: Consolidate the setgroups permission checks mnt: Clear mnt_expire during pivot_root mnt: Carefully set CL_UNPRIVILEGED in clone_mnt mnt: Move the clear of MNT_LOCKED from copy_tree to it's callers. umount: Do not allow unmounting rootfs. umount: Disallow unprivileged mount force mnt: Update unprivileged remount test mnt: Implicitly add MNT_NODEV on remount when it was implicitly added by mount
2014-12-16Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs pile #2 from Al Viro: "Next pile (and there'll be one or two more). The large piece in this one is getting rid of /proc/*/ns/* weirdness; among other things, it allows to (finally) make nameidata completely opaque outside of fs/namei.c, making for easier further cleanups in there" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: coda_venus_readdir(): use file_inode() fs/namei.c: fold link_path_walk() call into path_init() path_init(): don't bother with LOOKUP_PARENT in argument fs/namei.c: new helper (path_cleanup()) path_init(): store the "base" pointer to file in nameidata itself make default ->i_fop have ->open() fail with ENXIO make nameidata completely opaque outside of fs/namei.c kill proc_ns completely take the targets of /proc/*/ns/* symlinks to separate fs bury struct proc_ns in fs/proc copy address of proc_ns_ops into ns_common new helpers: ns_alloc_inum/ns_free_inum make proc_ns_operations work with struct ns_common * instead of void * switch the rest of proc_ns_operations to working with &...->ns netns: switch ->get()/->put()/->install()/->inum() to working with &net->ns make mntns ->get()/->put()/->install()/->inum() work with &mnt_ns->ns common object embedded into various struct ....ns
2014-12-13genirq: Prevent proc race against freeing of irq descriptorsThomas Gleixner
Since the rework of the sparse interrupt code to actually free the unused interrupt descriptors there exists a race between the /proc interfaces to the irq subsystem and the code which frees the interrupt descriptor. CPU0 CPU1 show_interrupts() desc = irq_to_desc(X); free_desc(desc) remove_from_radix_tree(); kfree(desc); raw_spinlock_irq(&desc->lock); /proc/interrupts is the only interface which can actively corrupt kernel memory via the lock access. /proc/stat can only read from freed memory. Extremly hard to trigger, but possible. The interfaces in /proc/irq/N/ are not affected by this because the removal of the proc file is serialized in procfs against concurrent readers/writers. The removal happens before the descriptor is freed. For architectures which have CONFIG_SPARSE_IRQ=n this is a non issue as the descriptor is never freed. It's merely cleared out with the irq descriptor lock held. So any concurrent proc access will either see the old correct value or the cleared out ones. Protect the lookup and access to the irq descriptor in show_interrupts() with the sparse_irq_lock. Provide kstat_irqs_usr() which is protecting the lookup and access with sparse_irq_lock and switch /proc/stat to use it. Document the existing kstat_irqs interfaces so it's clear that the caller needs to take care about protection. The users of these interfaces are either not affected due to SPARSE_IRQ=n or already protected against removal. Fixes: 1f5a5b87f78f "genirq: Implement a sane sparse_irq allocator" Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org
2014-12-11userns: Add a knob to disable setgroups on a per user namespace basisEric W. Biederman
- Expose the knob to user space through a proc file /proc/<pid>/setgroups A value of "deny" means the setgroups system call is disabled in the current processes user namespace and can not be enabled in the future in this user namespace. A value of "allow" means the segtoups system call is enabled. - Descendant user namespaces inherit the value of setgroups from their parents. - A proc file is used (instead of a sysctl) as sysctls currently do not allow checking the permissions at open time. - Writing to the proc file is restricted to before the gid_map for the user namespace is set. This ensures that disabling setgroups at a user namespace level will never remove the ability to call setgroups from a process that already has that ability. A process may opt in to the setgroups disable for itself by creating, entering and configuring a user namespace or by calling setns on an existing user namespace with setgroups disabled. Processes without privileges already can not call setgroups so this is a noop. Prodcess with privilege become processes without privilege when entering a user namespace and as with any other path to dropping privilege they would not have the ability to call setgroups. So this remains within the bounds of what is possible without a knob to disable setgroups permanently in a user namespace. Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2014-12-10Merge branch 'akpm' (patchbomb from Andrew)Linus Torvalds
Merge first patchbomb from Andrew Morton: - a few minor cifs fixes - dma-debug upadtes - ocfs2 - slab - about half of MM - procfs - kernel/exit.c - panic.c tweaks - printk upates - lib/ updates - checkpatch updates - fs/binfmt updates - the drivers/rtc tree - nilfs - kmod fixes - more kernel/exit.c - various other misc tweaks and fixes * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits) exit: pidns: fix/update the comments in zap_pid_ns_processes() exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting exit: exit_notify: re-use "dead" list to autoreap current exit: reparent: call forget_original_parent() under tasklist_lock exit: reparent: avoid find_new_reaper() if no children exit: reparent: introduce find_alive_thread() exit: reparent: introduce find_child_reaper() exit: reparent: document the ->has_child_subreaper checks exit: reparent: s/while_each_thread/for_each_thread/ in find_new_reaper() exit: reparent: fix the cross-namespace PR_SET_CHILD_SUBREAPER reparenting exit: reparent: fix the dead-parent PR_SET_CHILD_SUBREAPER reparenting exit: proc: don't try to flush /proc/tgid/task/tgid exit: release_task: fix the comment about group leader accounting exit: wait: drop tasklist_lock before psig->c* accounting exit: wait: don't use zombie->real_parent exit: wait: cleanup the ptrace_reparented() checks usermodehelper: kill the kmod_thread_locker logic usermodehelper: don't use CLONE_VFORK for ____call_usermodehelper() fs/hfs/catalog.c: fix comparison bug in hfs_cat_keycmp nilfs2: fix the nilfs_iget() vs. nilfs_new_inode() races ...
2014-12-10Merge branch 'nsfs' into for-nextAl Viro
2014-12-10kill proc_ns completelyAl Viro
procfs inodes need only the ns_ops part; nsfs inodes don't need it at all Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-12-10take the targets of /proc/*/ns/* symlinks to separate fsAl Viro
New pseudo-filesystem: nsfs. Targets of /proc/*/ns/* live there now. It's not mountable (not even registered, so it's not in /proc/filesystems, etc.). Files on it *are* bindable - we explicitly permit that in do_loopback(). This stuff lives in fs/nsfs.c now; proc_ns_fget() moved there as well. get_proc_ns() is a macro now (it's simply returning ->i_private; would have been an inline, if not for header ordering headache). proc_ns_inode() is an ex-parrot. The interface used in procfs is ns_get_path(path, task, ops) and ns_get_name(buf, size, task, ops). Dentries and inodes are never hashed; a non-counting reference to dentry is stashed in ns_common (removed by ->d_prune()) and reused by ns_get_path() if present. See ns_get_path()/ns_prune_dentry/nsfs_evict() for details of that mechanism. As the result, proc_ns_follow_link() has stopped poking in nd->path.mnt; it does nd_jump_link() on a consistent <vfsmount,dentry> pair it gets from ns_get_path(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-12-10exit: proc: don't try to flush /proc/tgid/task/tgidOleg Nesterov
proc_flush_task_mnt() always tries to flush task/pid, but this is pointless if we reap the leader. d_invalidate() is recursive, and if nothing else the next d_hash_and_lookup(tgid) should fail anyway. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Rik van Riel <riel@redhat.com> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10proc: task_state: ptrace_parent() doesn't need pid_alive() checkOleg Nesterov
p->ptrace != 0 means that release_task(p) was not called, so pid_alive() buys nothing and we can remove this check. Other callers already use it directly without additional checks. Note: with or without this patch ptrace_parent() can return the pointer to the freed task, this will be explained/fixed later. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Cc: Sterling Alexander <stalexan@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roland McGrath <roland@hack.frob.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10proc: task_state: move the main seq_printf() outside of rcu_read_lock()Oleg Nesterov
task_state() does seq_printf() under rcu_read_lock(), but this is only needed for task_tgid_nr_ns() and task_numa_group_id(). We can calculate tgid/ngid and drop rcu lock. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Cc: Sterling Alexander <stalexan@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roland McGrath <roland@hack.frob.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10proc: task_state: deuglify the max_fds calculationOleg Nesterov
1. The usage of fdt looks very ugly, it can't be NULL if ->files is not NULL. We can use "unsigned int max_fds" instead. 2. This also allows to move seq_printf(max_fds) outside of task_lock() and join it with the previous seq_printf(). See also the next patch. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Cc: Sterling Alexander <stalexan@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roland McGrath <roland@hack.frob.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10proc: task_state: read cred->group_info outside of task_lock()Oleg Nesterov
task_state() reads cred->group_info under task_lock() because a long ago it was task_struct->group_info and it was actually protected by task->alloc_lock. Today this task_unlock() after rcu_read_unlock() just adds the confusion, move task_unlock() up. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Cc: Sterling Alexander <stalexan@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roland McGrath <roland@hack.frob.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10fs/proc.c: use rb_entry_safe() instead of rb_entry()Nicolas Dichtel
Better to use existing macro that rewriting them. Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10procfs: fix error handling of proc_register()Debabrata Banerjee
proc_register() error paths are leaking inodes and directory refcounts. Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10fs/proc: use a rb tree for the directory entriesNicolas Dichtel
When a lot of netdevices are created, one of the bottleneck is the creation of proc entries. This serie aims to accelerate this part. The current implementation for the directories in /proc is using a single linked list. This is slow when handling directories with large numbers of entries (eg netdevice-related entries when lots of tunnels are opened). This patch replaces this linked list by a red-black tree. Here are some numbers: dummy30000.batch contains 30 000 times 'link add type dummy'. Before the patch: $ time ip -b dummy30000.batch real 2m31.950s user 0m0.440s sys 2m21.440s $ time rmmod dummy real 1m35.764s user 0m0.000s sys 1m24.088s After the patch: $ time ip -b dummy30000.batch real 2m0.874s user 0m0.448s sys 1m49.720s $ time rmmod dummy real 1m13.988s user 0m0.000s sys 1m1.008s The idea of improving this part was suggested by Thierry Herbelot. [akpm@linux-foundation.org: initialise proc_root.subdir at compile time] Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Thierry Herbelot <thierry.herbelot@6wind.com>. Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10mm: fix huge zero page accounting in smaps reportKirill A. Shutemov
As a small zero page, huge zero page should not be accounted in smaps report as normal page. For small pages we rely on vm_normal_page() to filter out zero page, but vm_normal_page() is not designed to handle pmds. We only get here due hackish cast pmd to pte in smaps_pte_range() -- pte and pmd format is not necessary compatible on each and every architecture. Let's add separate codepath to handle pmds. follow_trans_huge_pmd() will detect huge zero page for us. We would need pmd_dirty() helper to do this properly. The patch adds it to THP-enabled architectures which don't yet have one. [akpm@linux-foundation.org: use do_div to fix 32-bit build] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Tested-by: Fengwei Yin <yfw.kernel@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull VFS changes from Al Viro: "First pile out of several (there _definitely_ will be more). Stuff in this one: - unification of d_splice_alias()/d_materialize_unique() - iov_iter rewrite - killing a bunch of ->f_path.dentry users (and f_dentry macro). Getting that completed will make life much simpler for unionmount/overlayfs, since then we'll be able to limit the places sensitive to file _dentry_ to reasonably few. Which allows to have file_inode(file) pointing to inode in a covered layer, with dentry pointing to (negative) dentry in union one. Still not complete, but much closer now. - crapectomy in lustre (dead code removal, mostly) - "let's make seq_printf return nothing" preparations - assorted cleanups and fixes There _definitely_ will be more piles" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) copy_from_iter_nocache() new helper: iov_iter_kvec() csum_and_copy_..._iter() iov_iter.c: handle ITER_KVEC directly iov_iter.c: convert copy_to_iter() to iterate_and_advance iov_iter.c: convert copy_from_iter() to iterate_and_advance iov_iter.c: get rid of bvec_copy_page_{to,from}_iter() iov_iter.c: convert iov_iter_zero() to iterate_and_advance iov_iter.c: convert iov_iter_get_pages_alloc() to iterate_all_kinds iov_iter.c: convert iov_iter_get_pages() to iterate_all_kinds iov_iter.c: convert iov_iter_npages() to iterate_all_kinds iov_iter.c: iterate_and_advance iov_iter.c: macros for iterating over iov_iter kill f_dentry macro dcache: fix kmemcheck warning in switch_names new helper: audit_file() nfsd_vfs_write(): use file_inode() ncpfs: use file_inode() kill f_dentry uses lockd: get rid of ->f_path.dentry->d_sb ...
2014-12-04bury struct proc_ns in fs/procAl Viro
a) make get_proc_ns() return a pointer to struct ns_common b) mirror ns_ops in dentry->d_fsdata of ns dentries, so that is_mnt_ns_file() could get away with fewer dereferences. That way struct proc_ns becomes invisible outside of fs/proc/*.c Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-12-04copy address of proc_ns_ops into ns_commonAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-12-04make proc_ns_operations work with struct ns_common * instead of void *Al Viro
We can do that now. And kill ->inum(), while we are at it - all instances are identical. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-11-19Merge tag 'trace-seq-file-cleanup' of ↵Al Viro
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into for-next Pull the beginning of seq_file cleanup from Steven: "I'm looking to clean up the seq_file code and to eventually merge the trace_seq code with seq_file as well, since they basically do the same thing. Part of this process is to remove the return code of seq_printf() and friends as they are rather inconsistent. It is better to use the new function seq_has_overflowed() if you want to stop processing when the buffer is full. Note, if the buffer is full, the seq_file code will throw away the contents, allocate a bigger buffer, and then call your code again to fill in the data. The only thing that breaking out of the function early does is to save a little time which is probably never noticed. I started with patches from Joe Perches and modified them as well. There's many more places that need to be updated before we can convert seq_printf() and friends to return void. But this patch set introduces the seq_has_overflowed() and does some initial updates."
2014-11-19procfs: get rid of ->f_dentryAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-11-18x86, mpx: Introduce VM_MPX to indicate that a VMA is MPX specificQiaowei Ren
MPX-enabled applications using large swaths of memory can potentially have large numbers of bounds tables in process address space to save bounds information. These tables can take up huge swaths of memory (as much as 80% of the memory on the system) even if we clean them up aggressively. In the worst-case scenario, the tables can be 4x the size of the data structure being tracked. IOW, a 1-page structure can require 4 bounds-table pages. Being this huge, our expectation is that folks using MPX are going to be keen on figuring out how much memory is being dedicated to it. So we need a way to track memory use for MPX. If we want to specifically track MPX VMAs we need to be able to distinguish them from normal VMAs, and keep them from getting merged with normal VMAs. A new VM_ flag set only on MPX VMAs does both of those things. With this flag, MPX bounds-table VMAs can be distinguished from other VMAs, and userspace can also walk /proc/$pid/smaps to get memory usage for MPX. In addition to this flag, we also introduce a special ->vm_ops specific to MPX VMAs (see the patch "add MPX specific mmap interface"), but currently different ->vm_ops do not by themselves prevent VMA merging, so we still need this flag. We understand that VM_ flags are scarce and are open to other options. Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: linux-mm@kvack.org Cc: linux-mips@linux-mips.org Cc: Dave Hansen <dave@sr71.net> Link: http://lkml.kernel.org/r/20141114151825.565625B3@viggo.jf.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-11-05fs: Convert show_fdinfo functions to voidJoe Perches
seq_printf functions shouldn't really check the return value. Checking seq_has_overflowed() occasionally is used instead. Update vfs documentation. Link: http://lkml.kernel.org/p/e37e6e7b76acbdcc3bb4ab2a57c8f8ca1ae11b9a.1412031505.git.joe@perches.com Cc: David S. Miller <davem@davemloft.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Joe Perches <joe@perches.com> [ did a few clean ups ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-10-14mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY clearedPeter Feiner
For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf241451 ("mm: uncached vma support with writenotify"). Signed-off-by: Peter Feiner <pfeiner@google.com> Reported-by: Peter Feiner <pfeiner@google.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-13Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "The big thing in this pile is Eric's unmount-on-rmdir series; we finally have everything we need for that. The final piece of prereqs is delayed mntput() - now filesystem shutdown always happens on shallow stack. Other than that, we have several new primitives for iov_iter (Matt Wilcox, culled from his XIP-related series) pushing the conversion to ->read_iter()/ ->write_iter() a bit more, a bunch of fs/dcache.c cleanups and fixes (including the external name refcounting, which gives consistent behaviour of d_move() wrt procfs symlinks for long and short names alike) and assorted cleanups and fixes all over the place. This is just the first pile; there's a lot of stuff from various people that ought to go in this window. Starting with unionmount/overlayfs mess... ;-/" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (60 commits) fs/file_table.c: Update alloc_file() comment vfs: Deduplicate code shared by xattr system calls operating on paths reiserfs: remove pointless forward declaration of struct nameidata don't need that forward declaration of struct nameidata in dcache.h anymore take dname_external() into fs/dcache.c let path_init() failures treated the same way as subsequent link_path_walk() fix misuses of f_count() in ppp and netlink ncpfs: use list_for_each_entry() for d_subdirs walk vfs: move getname() from callers to do_mount() gfs2_atomic_open(): skip lookups on hashed dentry [infiniband] remove pointless assignments gadgetfs: saner API for gadgetfs_create_file() f_fs: saner API for ffs_sb_create_file() jfs: don't hash direct inode [s390] remove pointless assignment of ->f_op in vmlogrdr ->open() ecryptfs: ->f_op is never NULL android: ->f_op is never NULL nouveau: __iomem misannotations missing annotation in fs/file.c fs: namespace: suppress 'may be used uninitialized' warnings ...
2014-10-10Merge branch 'for-3.18' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "Nothing too interesting. Just a handful of cleanup patches" * 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: Revert "cgroup: remove redundant variable in cgroup_mount()" cgroup: remove redundant variable in cgroup_mount() cgroup: fix missing unlock in cgroup_release_agent() cgroup: remove CGRP_RELEASABLE flag perf/cgroup: Remove perf_put_cgroup() cgroup: remove redundant check in cgroup_ino() cpuset: simplify proc_cpuset_show() cgroup: simplify proc_cgroup_show() cgroup: use a per-cgroup work for release agent cgroup: remove bogus comments cgroup: remove redundant code in cgroup_rmdir() cgroup: remove some useless forward declarations cgroup: fix a typo in comment.
2014-10-09mm/balloon_compaction: add vmstat counters and kpageflags bitKonstantin Khlebnikov
Always mark pages with PageBalloon even if balloon compaction is disabled and expose this mark in /proc/kpageflags as KPF_BALLOON. Also this patch adds three counters into /proc/vmstat: "balloon_inflate", "balloon_deflate" and "balloon_migrate". They accumulate balloon activity. Current size of balloon is (balloon_inflate - balloon_deflate) pages. All generic balloon code now gathered under option CONFIG_MEMORY_BALLOON. It should be selected by ballooning driver which wants use this feature. Currently virtio-balloon is the only user. Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com> Cc: Rafael Aquini <aquini@redhat.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09mm: softdirty: unmapped addresses between VMAs are cleanPeter Feiner
If a /proc/pid/pagemap read spans a [VMA, an unmapped region, then a VM_SOFTDIRTY VMA], the virtual pages in the unmapped region are reported as softdirty. Here's a program to demonstrate the bug: int main() { const uint64_t PAGEMAP_SOFTDIRTY = 1ul << 55; uint64_t pme[3]; int fd = open("/proc/self/pagemap", O_RDONLY);; char *m = mmap(NULL, 3 * getpagesize(), PROT_READ, MAP_ANONYMOUS | MAP_SHARED, -1, 0); munmap(m + getpagesize(), getpagesize()); pread(fd, pme, 24, (unsigned long) m / getpagesize() * 8); assert(pme[0] & PAGEMAP_SOFTDIRTY); /* passes */ assert(!(pme[1] & PAGEMAP_SOFTDIRTY)); /* fails */ assert(pme[2] & PAGEMAP_SOFTDIRTY); /* passes */ return 0; } (Note that all pages in new VMAs are softdirty until cleared). Tested: Used the program given above. I'm going to include this code in a selftest in the future. [n-horiguchi@ah.jp.nec.com: prevent pagemap_pte_range() from overrunning] Signed-off-by: Peter Feiner <pfeiner@google.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09mempolicy: fix show_numa_map() vs exec() + do_set_mempolicy() raceOleg Nesterov
9e7814404b77 "hold task->mempolicy while numa_maps scans." fixed the race with the exiting task but this is not enough. The current code assumes that get_vma_policy(task) should either see task->mempolicy == NULL or it should be equal to ->task_mempolicy saved by hold_task_mempolicy(), so we can never race with __mpol_put(). But this can only work if we can't race with do_set_mempolicy(), and thus we can't race with another do_set_mempolicy() or do_exit() after that. However, do_set_mempolicy()->down_write(mmap_sem) can not prevent this race. This task can exec, change it's ->mm, and call do_set_mempolicy() after that; in this case they take 2 different locks. Change hold_task_mempolicy() to use get_task_policy(), it never returns NULL, and change show_numa_map() to use __get_vma_policy() or fall back to proc_priv->task_mempolicy. Note: this is the minimal fix, we will cleanup this code later. I think hold_task_mempolicy() and release_task_mempolicy() should die, we can move this logic into show_numa_map(). Or we can move get_task_policy() outside of ->mmap_sem and !CONFIG_NUMA code at least. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/kcore.c: don't add modules range to kcore if it's equal to vmcore rangeBaoquan He
On some ARCHs modules range is eauql to vmalloc range. E.g on i686 "#define MODULES_VADDR VMALLOC_START" "#define MODULES_END VMALLOC_END" This will cause 2 duplicate program segments in /proc/kcore, and no flag to indicate they are different. This is confusing. And usually people who need check the elf header or read the content of kcore will check memory ranges. Two program segments which are the same are unnecessary. So check if the modules range is equal to vmalloc range. If so, just skip adding the modules range. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09proc/maps: make vm_is_stack() logic namespace-friendlyOleg Nesterov
- Rename vm_is_stack() to task_of_stack() and change it to return "struct task_struct *" rather than the global (and thus wrong in general) pid_t. - Add the new pid_of_stack() helper which calls task_of_stack() and uses the right namespace to report the correct pid_t. Unfortunately we need to define this helper twice, in task_mmu.c and in task_nommu.c. perhaps it makes sense to add fs/proc/util.c and move at least pid_of_stack/task_of_stack there to avoid the code duplication. - Change show_map_vma() and show_numa_map() to use the new helper. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Greg Ungerer <gerg@uclinux.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09proc/maps: replace proc_maps_private->pid with "struct inode *inode"Oleg Nesterov
m_start() can use get_proc_task() instead, and "struct inode *" provides more potentially useful info, see the next changes. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Greg Ungerer <gerg@uclinux.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_nommu.c: don't use priv->task->mmOleg Nesterov
I do not know if CONFIG_PREEMPT/SMP is possible without CONFIG_MMU but the usage of task->mm in m_stop(). The task can exit/exec before we take mmap_sem, in this case m_stop() can hit NULL or unlock the wrong rw_semaphore. Also, this code uses priv->task != NULL to decide whether we need up_read/mmput. This is correct, but we will probably kill priv->task. Change m_start/m_stop to rely on IS_ERR_OR_NULL() like task_mmu.c does. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Greg Ungerer <gerg@uclinux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_nommu.c: shift mm_access() from m_start() to proc_maps_open()Oleg Nesterov
Copy-and-paste the changes from "fs/proc/task_mmu.c: shift mm_access() from m_start() to proc_maps_open()" into task_nommu.c. Change maps_open() to initialize priv->mm using proc_mem_open(), m_start() can rely on atomic_inc_not_zero(mm_users) like task_mmu.c does. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Greg Ungerer <gerg@uclinux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_nommu.c: change maps_open() to use __seq_open_private()Oleg Nesterov
Cleanup and preparation. maps_open() can use __seq_open_private() like proc_maps_open() does. [akpm@linux-foundation.org: deuglify] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Greg Ungerer <gerg@uclinux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_mmu.c: update m->version in the main loop in m_start()Oleg Nesterov
Change the main loop in m_start() to update m->version. Mostly for consistency, but this can help to avoid the same loop if the very 1st ->show() fails due to seq_overflow(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_mmu.c: reintroduce m->version logicOleg Nesterov
Add the "last_addr" optimization back. Like before, every ->show() method checks !seq_overflow() and sets m->version = vma->vm_start. However, it also checks that m_next_vma(vma) != NULL, otherwise it sets m->version = -1 for the lockless "EOF" fast-path in m_start(). m_start() can simply do find_vma() + m_next_vma() if last_addr is not zero, the code looks clear and simple and this case is clearly separated from "scan vmas" path. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_mmu.c: introduce m_next_vma() helperOleg Nesterov
Extract the tail_vma/vm_next calculation from m_next() into the new trivial helper, m_next_vma(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_mmu.c: simplify m_start() to make it readableOleg Nesterov
Now that m->version is gone we can cleanup m_start(). In particular, - Remove the "unsigned long" typecast, m->index can't be negative or exceed ->map_count. But lets use "unsigned int pos" to make it clear that "pos < map_count" is safe. - Remove the unnecessary "vma != NULL" check in the main loop. It can't be NULL unless we have a vm bug. - This also means that "pos < map_count" case can simply return the valid vma and avoid "goto" and subsequent checks. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_mmu.c: kill the suboptimal and confusing m->version logicOleg Nesterov
m_start() carefully documents, checks, and sets "m->version = -1" if we are going to return NULL. The only problem is that we will be never called again if m_start() returns NULL, so this is simply pointless and misleading. Otoh, ->show() methods m->version = 0 if vma == tail_vma and this is just wrong, we want -1 in this case. And in fact we also want -1 if ->vm_next == NULL and ->tail_vma == NULL. And it is not used consistently, the "scan vmas" loop in m_start() should update last_addr too. Finally, imo the whole "last_addr" logic in m_start() looks horrible. find_vma(last_addr) is called unconditionally even if we are not going to use the result. But the main problem is that this code participates in tail_vma-or-NULL mess, and this looks simply unfixable. Remove this optimization. We will add it back after some cleanups. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_mmu.c: shift "priv->task = NULL" from m_start() to m_stop()Oleg Nesterov
1. There is no reason to reset ->tail_vma in m_start(), if we return IS_ERR_OR_NULL() it won't be used. 2. m_start() also clears priv->task to ensure that m_stop() won't use the stale pointer if we fail before get_task_struct(). But this is ugly and confusing, move this initialization in m_stop(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_mmu.c: cleanup the "tail_vma" horror in m_next()Oleg Nesterov
1. Kill the first "vma != NULL" check. Firstly this is not possible, m_next() won't be called if ->start() or the previous ->next() returns NULL. And if it was possible the 2nd "vma != tail_vma" check is buggy, we should not wrongly return ->tail_vma. 2. Make this function readable. The logic is very simple, we should return check "vma != tail" once and return "vm_next || tail_vma". Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_mmu.c: simplify the vma_stop() logicOleg Nesterov
m_start() drops ->mmap_sem and does mmput() if it retuns vsyscall vma. This is because in this case m_stop()->vma_stop() obviously can't use gate_vma->vm_mm. Now that we have proc_maps_private->mm we can simplify this logic: - Change m_start() to return with ->mmap_sem held unless it returns IS_ERR_OR_NULL(). - Change vma_stop() to use priv->mm and avoid the ugly vma checks, this makes "vm_area_struct *vma" unnecessary. - This also allows m_start() to use vm_stop(). - Cleanup m_next() to follow the new locking rule. Note: m_stop() looks very ugly, and this temporary uglifies it even more. Fixed by the next change. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_mmu.c: shift mm_access() from m_start() to proc_maps_open()Oleg Nesterov
A simple test-case from Kirill Shutemov cat /proc/self/maps >/dev/null chmod +x /proc/self/net/packet exec /proc/self/net/packet makes lockdep unhappy, cat/exec take seq_file->lock + cred_guard_mutex in the opposite order. It's a false positive and probably we should not allow "chmod +x" on proc files. Still I think that we should avoid mm_access() and cred_guard_mutex in sys_read() paths, security checking should happen at open time. Besides, this doesn't even look right if the task changes its ->mm between m_stop() and m_start(). Add the new "mm_struct *mm" member into struct proc_maps_private and change proc_maps_open() to initialize it using proc_mem_open(). Change m_start() to use priv->mm if atomic_inc_not_zero(mm_users) succeeds or return NULL (eof) otherwise. The only complication is that proc_maps_open() users should additionally do mmdrop() in fop->release(), add the new proc_map_release() helper for that. Note: this is the user-visible change, if the task execs after open("maps") the new ->mm won't be visible via this file. I hope this is fine, and this matches /proc/pid/mem bahaviour. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09proc: introduce proc_mem_open()Oleg Nesterov
Extract the mm_access() code from __mem_open() into the new helper, proc_mem_open(), the next patch will add another caller. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09fs/proc/task_mmu.c: unify/simplify do_maps_open() and numa_maps_open()Oleg Nesterov
do_maps_open() and numa_maps_open() are overcomplicated, they could use __seq_open_private(). Plus they do the same, just sizeof(*priv) Change them to use a new simple helper, proc_maps_open(ops, psize). This simplifies the code and allows us to do the next changes. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>