- Aug 22, 2018
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Omar Sandoval authored
The vmcoreinfo information is useful for runtime debugging tools, not just for crash dumps. A lot of this information can be determined by other means, but this is much more convenient, and it only adds a page at most to the file. Link: http://lkml.kernel.org/r/fddbcd08eed76344863303878b12de1c1e2a04b6.1531953780.git.osandov@fb.com Signed-off-by:
Omar Sandoval <osandov@fb.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Bhupesh Sharma <bhsharma@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: James Morse <james.morse@arm.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Omar Sandoval authored
The current code does a full search of the segment list every time for every page. This is wasteful, since it's almost certain that the next page will be in the same segment. Instead, check if the previous segment covers the current page before doing the list search. Link: http://lkml.kernel.org/r/fd346c11090cf93d867e01b8d73a6567c5ac6361.1531953780.git.osandov@fb.com Signed-off-by:
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Omar Sandoval authored
Currently, the ELF file header, program headers, and note segment are allocated all at once, in some icky code dating back to 2.3. Programs tend to read the file header, then the program headers, then the note segment, all separately, so this is a waste of effort. It's cleaner and more efficient to handle the three separately. Link: http://lkml.kernel.org/r/19c92cbad0e11f6103ff3274b2e7a7e51a1eb74b.1531953780.git.osandov@fb.com Signed-off-by:
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Omar Sandoval authored
Now that we're using an rwsem, we can hold it during the entirety of read_kcore() and have a common return path. This is preparation for the next change. [akpm@linux-foundation.org: fix locking bug reported by Tetsuo Handa] Link: http://lkml.kernel.org/r/d7cfbc1e8a76616f3b699eaff9df0a2730380534.1531953780.git.osandov@fb.com Signed-off-by:
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Omar Sandoval authored
There's a theoretical race condition that will cause /proc/kcore to miss a memory hotplug event: CPU0 CPU1 // hotplug event 1 kcore_need_update = 1 open_kcore() open_kcore() kcore_update_ram() kcore_update_ram() // Walk RAM // Walk RAM __kcore_update_ram() __kcore_update_ram() kcore_need_update = 0 // hotplug event 2 kcore_need_update = 1 kcore_need_update = 0 Note that CPU1 set up the RAM kcore entries with the state after hotplug event 1 but cleared the flag for hotplug event 2. The RAM entries will therefore be stale until there is another hotplug event. This is an extremely unlikely sequence of events, but the fix makes the synchronization saner, anyways: we serialize the entire update sequence, which means that whoever clears the flag will always succeed in replacing the kcore list. Link: http://lkml.kernel.org/r/6106c509998779730c12400c1b996425df7d7089.1531953780.git.osandov@fb.com Signed-off-by: -
Omar Sandoval authored
Now we only need kclist_lock from user context and at fs init time, and the following changes need to sleep while holding the kclist_lock. Link: http://lkml.kernel.org/r/521ba449ebe921d905177410fee9222d07882f0d.1531953780.git.osandov@fb.com Signed-off-by:
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Omar Sandoval authored
The memory hotplug notifier kcore_callback() only needs kclist_lock to prevent races with __kcore_update_ram(), but we can easily eliminate that race by using an atomic xchg() in __kcore_update_ram(). This is preparation for converting kclist_lock to an rwsem. Link: http://lkml.kernel.org/r/0a4bc89f4dbde8b5b2ea309f7b4fb6a85fe29df2.1531953780.git.osandov@fb.com Signed-off-by:
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Omar Sandoval authored
Patch series "/proc/kcore improvements", v4. This series makes a few improvements to /proc/kcore. It fixes a couple of small issues in v3 but is otherwise the same. Patches 1, 2, and 3 are prep patches. Patch 4 is a fix/cleanup. Patch 5 is another prep patch. Patches 6 and 7 are optimizations to ->read(). Patch 8 makes it possible to enable CRASH_CORE on any architecture, which is needed for patch 9. Patch 9 adds vmcoreinfo to /proc/kcore. This patch (of 9): kclist_add() is only called at init time, so there's no point in grabbing any locks. We're also going to replace the rwlock with a rwsem, which we don't want to try grabbing during early boot. While we're here, mark kclist_add() with __init so that we'll get a warning if it's called from non-init code. Link: http://lkml.kernel.org/r/98208db1faf167aa8b08eebfa968d95c70527739.1531953780.git.osandov@fb.com Signed-off-by:
Bhupesh Sharma <bhsharma@redhat.com> Tested-by:
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James Morse authored
elf_kcore_store_hdr() uses __pa() to find the physical address of KCORE_RAM or KCORE_TEXT entries exported as program headers. This trips CONFIG_DEBUG_VIRTUAL's checks, as the KCORE_TEXT entries are not in the linear map. Handle these two cases separately, using __pa_symbol() for the KCORE_TEXT entries. Link: http://lkml.kernel.org/r/20180711131944.15252-1-james.morse@arm.com Signed-off-by:
James Morse <james.morse@arm.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Omar Sandoval <osandov@fb.com> Signed-off-by:
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Souptick Joarder authored
Use new return type vm_fault_t for fault handler in struct vm_operations_struct. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. See 1c8f4220 ("mm: change return type to vm_fault_t") for reference. Link: http://lkml.kernel.org/r/20180702153325.GA3875@jordon-HP-15-Notebook-PC Signed-off-by:
Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by:
Matthew Wilcox <mawilcox@microsoft.com> Cc: Ganesh Goudar <ganeshgr@chelsio.com> Cc: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com> Cc: David S. Miller <davem@davemloft.net> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by:
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Alexey Dobriyan authored
Number of CPUs is never high enough to force 64-bit arithmetic. Save couple of bytes on x86_64. Link: http://lkml.kernel.org/r/20180627200710.GC18434@avx2 Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by:
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Alexey Dobriyan authored
Link: http://lkml.kernel.org/r/20180627200614.GB18434@avx2 Signed-off-by:
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Alexey Dobriyan authored
->latency_record is defined as struct latency_record[LT_SAVECOUNT]; so use the same macro whie iterating. Link: http://lkml.kernel.org/r/20180627200534.GA18434@avx2 Signed-off-by:
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Alexey Dobriyan authored
Code checks if write is done by current to its own attributes. For that get/put pair is unnecessary as it can be done under RCU. Note: rcu_read_unlock() can be done even earlier since pointer to a task is not dereferenced. It depends if /proc code should look scary or not: rcu_read_lock(); task = pid_task(...); rcu_read_unlock(); if (!task) return -ESRCH; if (task != current) return -EACCESS: P.S.: rename "length" variable. Code like this length = -EINVAL; should not exist. Link: http://lkml.kernel.org/r/20180627200218.GF18113@avx2 Signed-off-by:
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Alexey Dobriyan authored
Link: http://lkml.kernel.org/r/20180627195427.GE18113@avx2 Signed-off-by:
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Alexey Dobriyan authored
Readdir context is thread local, so ->pos is thread local, move it out of readlock. Link: http://lkml.kernel.org/r/20180627195339.GD18113@avx2 Signed-off-by:
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Arnd Bergmann authored
get_monotonic_boottime() is deprecated and uses the old timespec type. Let's convert /proc/uptime to use ktime_get_boottime_ts64(). Link: http://lkml.kernel.org/r/20180620081746.282742-1-arnd@arndb.de Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Acked-by:
Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Deepa Dinamani <deepa.kernel@gmail.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by:
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Alexey Dobriyan authored
24074a35 ("proc: Make inline name size calculation automatic") started to put PDE allocations into kmalloc-256 which is unnecessary as ~40 character names are very rare. Put allocation back into kmalloc-192 cache for 64-bit non-debug builds. Put BUILD_BUG_ON to know when PDE size has gotten out of control. [adobriyan@gmail.com: fix BUILD_BUG_ON breakage on powerpc64] Link: http://lkml.kernel.org/r/20180703191602.GA25521@avx2 Link: http://lkml.kernel.org/r/20180617215732.GA24688@avx2 Signed-off-by:
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Dennis Zhou (Facebook) authored
Currently, percpu memory only exposes allocation and utilization information via debugfs. This more or less is only really useful for understanding the fragmentation and allocation information at a per-chunk level with a few global counters. This is also gated behind a config. BPF and cgroup, for example, have seen an increase in use causing increased use of percpu memory. Let's make it easier for someone to identify how much memory is being used. This patch adds the "Percpu" stat to meminfo to more easily look up how much percpu memory is in use. This number includes the cost for all allocated backing pages and not just insight at the per a unit, per chunk level. Metadata is excluded. I think excluding metadata is fair because the backing memory scales with the numbere of cpus and can quickly outweigh the metadata. It also makes this calculation light. Link: http://lkml.kernel.org/r/20180807184723.74919-1-dennisszhou@gmail.com Signed-off-by:
Dennis Zhou <dennisszhou@gmail.com> Acked-by:
Tejun Heo <tj@kernel.org> Acked-by:
Roman Gushchin <guro@fb.com> Reviewed-by:
David Rientjes <rientjes@google.com> Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by:
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Andrew Morton authored
Rather than in vm_area_alloc(). To ensure that the various oddball stack-based vmas are in a good state. Some of the callers were zeroing them out, others were not. Acked-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by:
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Vlastimil Babka authored
The /proc/pid/smaps_rollup file is currently implemented via the m_start/m_next/m_stop seq_file iterators shared with the other maps files, that iterate over vma's. However, the rollup file doesn't print anything for each vma, only accumulate the stats. There are some issues with the current code as reported in [1] - the accumulated stats can get skewed if seq_file start()/stop() op is called multiple times, if show() is called multiple times, and after seeks to non-zero position. Patch [1] fixed those within existing design, but I believe it is fundamentally wrong to expose the vma iterators to the seq_file mechanism when smaps_rollup shows logically a single set of values for the whole address space. This patch thus refactors the code to provide a single "value" at offset 0, with vma iteration to gather the stats done internally. This fixes the situations where results are skewed, and simplifies the code, especially in show_smap(), at the expense of somewhat less code reuse. [1] https://marc.info/?l=linux-mm&m=151927723128134&w=2 [vbabka@suse.c: use seq_file infrastructure] Link: http://lkml.kernel.org/r/bf4525b0-fd5b-4c4c-2cb3-adee3dd95a48@suse.cz Link: http://lkml.kernel.org/r/20180723111933.15443-5-vbabka@suse.cz Signed-off-by:
Daniel Colascione <dancol@google.com> Reviewed-by:
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Vlastimil Babka authored
To prepare for handling /proc/pid/smaps_rollup differently from /proc/pid/smaps factor out from show_smap() printing the parts of output that are common for both variants, which is the bulk of the gathered memory stats. [vbabka@suse.cz: add const, per Alexey] Link: http://lkml.kernel.org/r/b45f319f-cd04-337b-37f8-77f99786aa8a@suse.cz Link: http://lkml.kernel.org/r/20180723111933.15443-4-vbabka@suse.cz Signed-off-by:
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Vlastimil Babka authored
To prepare for handling /proc/pid/smaps_rollup differently from /proc/pid/smaps factor out vma mem stats gathering from show_smap() - it will be used by both. Link: http://lkml.kernel.org/r/20180723111933.15443-3-vbabka@suse.cz Signed-off-by:
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Vlastimil Babka authored
Patch series "cleanups and refactor of /proc/pid/smaps*". The recent regression in /proc/pid/smaps made me look more into the code. Especially the issues with smaps_rollup reported in [1] as explained in Patch 4, which fixes them by refactoring the code. Patches 2 and 3 are preparations for that. Patch 1 is me realizing that there's a lot of boilerplate left from times where we tried (unsuccessfuly) to mark thread stacks in the output. Originally I had also plans to rework the translation from /proc/pid/*maps* file offsets to the internal structures. Now the offset means "vma number", which is not really stable (vma's can come and go between read() calls) and there's an extra caching of last vma's address. My idea was that offsets would be interpreted directly as addresses, which would also allow meaningful seeks (see the ugly seek_to_smaps_entry() in tools/testing/selftests/vm/mlock2.h). However loff_t is (signed) long long so that might be insufficient somewhere for the unsigned long addresses. So the result is fixed issues with skewed /proc/pid/smaps_rollup results, simpler smaps code, and a lot of unused code removed. [1] https://marc.info/?l=linux-mm&m=151927723128134&w=2 This patch (of 4): Commit b7643757 ("procfs: mark thread stack correctly in proc/<pid>/maps") introduced differences between /proc/PID/maps and /proc/PID/task/TID/maps to mark thread stacks properly, and this was also done for smaps and numa_maps. However it didn't work properly and was ultimately removed by commit b18cb64e ("fs/proc: Stop trying to report thread stacks"). Now the is_pid parameter for the related show_*() functions is unused and we can remove it together with wrapper functions and ops structures that differ for PID and TID cases only in this parameter. Link: http://lkml.kernel.org/r/20180723111933.15443-2-vbabka@suse.cz Signed-off-by:
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Ian Kent authored
autofs_sbi() does not check the superblock magic number to verify it has been given an autofs super block. Link: http://lkml.kernel.org/r/153475422934.17131.7563724552005298277.stgit@pluto.themaw.net Reported-by:
<syzbot+87c3c541582e56943277@syzkaller.appspotmail.com> Signed-off-by:
Ian Kent <raven@themaw.net> Reviewed-by:
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- Aug 17, 2018
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Colin Ian King authored
Pointer uwq is being assigned but is never used hence it is redundant and can be removed. Cleans up clang warning: warning: variable 'uwq' set but not used [-Wunused-but-set-variable] Link: http://lkml.kernel.org/r/20180717090802.18357-1-colin.king@canonical.com Signed-off-by:
Colin Ian King <colin.king@canonical.com> Reviewed-by:
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Kirill Tkhai authored
We need to distinguish the situations when shrinker has very small amount of objects (see vfs_pressure_ratio() called from super_cache_count()), and when it has no objects at all. Currently, in the both of these cases, shrinker::count_objects() returns 0. The patch introduces new SHRINK_EMPTY return value, which will be used for "no objects at all" case. It's is a refactoring mostly, as SHRINK_EMPTY is replaced by 0 by all callers of do_shrink_slab() in this patch, and all the magic will happen in further. Link: http://lkml.kernel.org/r/153063069574.1818.11037751256699341813.stgit@localhost.localdomain Signed-off-by:
Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by:
Vladimir Davydov <vdavydov.dev@gmail.com> Tested-by:
Shakeel Butt <shakeelb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <jbacik@fb.com> Cc: Li RongQing <lirongqing@baidu.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matthias Kaehlcke <mka@chromium.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Roman Gushchin <guro@fb.com> Cc: Sahitya Tummala <stummala@codeaurora.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Signed-off-by:
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Kirill Tkhai authored
Add list_lru::shrinker_id field and populate it by registered shrinker id. This will be used to set correct bit in memcg shrinkers map by lru code in next patches, after there appeared the first related to memcg element in list_lru. Link: http://lkml.kernel.org/r/153063059758.1818.14866596416857717800.stgit@localhost.localdomain Signed-off-by:
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Kirill Tkhai authored
Do two list_lru_init_memcg() calls after prealloc_super(). destroy_unused_super() in fail path is OK with this. Next patch needs such the order. Link: http://lkml.kernel.org/r/153063058712.1818.3382490999719078571.stgit@localhost.localdomain Signed-off-by:
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Shakeel Butt authored
The buffer_head can consume a significant amount of system memory and is directly related to the amount of page cache. In our production environment we have observed that a lot of machines are spending a significant amount of memory as buffer_head and can not be left as system memory overhead. Charging buffer_head is not as simple as adding __GFP_ACCOUNT to the allocation. The buffer_heads can be allocated in a memcg different from the memcg of the page for which buffer_heads are being allocated. One concrete example is memory reclaim. The reclaim can trigger I/O of pages of any memcg on the system. So, the right way to charge buffer_head is to extract the memcg from the page for which buffer_heads are being allocated and then use targeted memcg charging API. [shakeelb@google.com: use __GFP_ACCOUNT for directed memcg charging] Link: http://lkml.kernel.org/r/20180702220208.213380-1-shakeelb@google.com Link: http://lkml.kernel.org/r/20180627191250.209150-3-shakeelb@google.com Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Greg Thelen <gthelen@google.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Roman Gushchin <guro@fb.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Shakeel Butt authored
Patch series "Directed kmem charging", v8. The Linux kernel's memory cgroup allows limiting the memory usage of the jobs running on the system to provide isolation between the jobs. All the kernel memory allocated in the context of the job and marked with __GFP_ACCOUNT will also be included in the memory usage and be limited by the job's limit. The kernel memory can only be charged to the memcg of the process in whose context kernel memory was allocated. However there are cases where the allocated kernel memory should be charged to the memcg different from the current processes's memcg. This patch series contains two such concrete use-cases i.e. fsnotify and buffer_head. The fsnotify event objects can consume a lot of system memory for large or unlimited queues if there is either no or slow listener. The events are allocated in the context of the event producer. However they should be charged to the event consumer. Similarly the buffer_head objects can be allocated in a memcg different from the memcg of the page for which buffer_head objects are being allocated. To solve this issue, this patch series introduces mechanism to charge kernel memory to a given memcg. In case of fsnotify events, the memcg of the consumer can be used for charging and for buffer_head, the memcg of the page can be charged. For directed charging, the caller can use the scope API memalloc_[un]use_memcg() to specify the memcg to charge for all the __GFP_ACCOUNT allocations within the scope. This patch (of 2): A lot of memory can be consumed by the events generated for the huge or unlimited queues if there is either no or slow listener. This can cause system level memory pressure or OOMs. So, it's better to account the fsnotify kmem caches to the memcg of the listener. However the listener can be in a different memcg than the memcg of the producer and these allocations happen in the context of the event producer. This patch introduces remote memcg charging API which the producer can use to charge the allocations to the memcg of the listener. There are seven fsnotify kmem caches and among them allocations from dnotify_struct_cache, dnotify_mark_cache, fanotify_mark_cache and inotify_inode_mark_cachep happens in the context of syscall from the listener. So, SLAB_ACCOUNT is enough for these caches. The objects from fsnotify_mark_connector_cachep are not accounted as they are small compared to the notification mark or events and it is unclear whom to account connector to since it is shared by all events attached to the inode. The allocations from the event caches happen in the context of the event producer. For such caches we will need to remote charge the allocations to the listener's memcg. Thus we save the memcg reference in the fsnotify_group structure of the listener. This patch has also moved the members of fsnotify_group to keep the size same, at least for 64 bit build, even with additional member by filling the holes. [shakeelb@google.com: use GFP_KERNEL_ACCOUNT rather than open-coding it] Link: http://lkml.kernel.org/r/20180702215439.211597-1-shakeelb@google.com Link: http://lkml.kernel.org/r/20180627191250.209150-2-shakeelb@google.com Signed-off-by:
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Jens Axboe authored
a_ops->readpages() is only ever used for read-ahead. Ensure that we pass this information down to the block layer. Link: http://lkml.kernel.org/r/20180621010725.17813-5-axboe@kernel.dk Signed-off-by:
Jens Axboe <axboe@kernel.dk> Reviewed-by:
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Jens Axboe authored
a_ops->readpages() is only ever used for read-ahead. Ensure that we pass this information down to the block layer. Link: http://lkml.kernel.org/r/20180621010725.17813-4-axboe@kernel.dk Signed-off-by:
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Jens Axboe authored
a_ops->readpages() is only ever used for read-ahead, yet we don't flag the IO being submitted as such. Fix that up. Any file system that uses mpage_readpages() as its ->readpages() implementation will now get this right. Since we're passing in whether the IO is read-ahead or not, we don't need to pass in the 'gfp' separately, as it is dependent on the IO being read-ahead. Kill off that member. Add some documentation notes on ->readpages() being purely for read-ahead. Link: http://lkml.kernel.org/r/20180621010725.17813-3-axboe@kernel.dk Signed-off-by:
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Jens Axboe authored
Patch series "Submit ->readpages() IO as read-ahead", v4. The only caller of ->readpages() is from read-ahead, yet we don't submit IO flagged with REQ_RAHEAD. This means we don't see it in blktrace, for instance, which is a shame. Additionally, it's preventing further functional changes in the block layer for deadling with read-ahead more intelligently. We already make assumptions about ->readpages() just being for read-ahead in the mpage implementation, using readahead_gfp_mask(mapping) as out GFP mask of choice. This small series fixes up mpage_readpages() to submit with REQ_RAHEAD, which takes care of file systems using mpage_readpages(). The first patch is a prep patch, that makes do_mpage_readpage() take an argument structure. This patch (of 4): We're currently passing 8 arguments to this function, clean it up a bit by packing the arguments in an args structure we pass to it. No intentional functional changes in this patch. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20180621010725.17813-2-axboe@kernel.dk Signed-off-by:
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NeilBrown authored
The documentation for seq_file suggests that it is necessary to be able to move the iterator to a given offset, however that is not the case. If the iterator is stored in the private data and is stable from one read() syscall to the next, it is only necessary to support first/next interactions. Implementing this in a client is a little clumsy. - if ->start() is given a pos of zero, it should go to start of sequence. - if ->start() is given the name pos that was given to the most recent next() or start(), it should restore the iterator to state just before that last call - if ->start is given another number, it should set the iterator one beyond the start just before the last ->start or ->next call. Also, the documentation says that the implementation can interpret the pos however it likes (other than zero meaning start), but seq_file increments the pos sometimes which does impose on the implementation. This patch simplifies the interface for first/next iteration and simplifies the code, while maintaining complete backward compatability. Now: - if ->start() is given a pos of zero, it should return an iterator placed at the start of the sequence - if ->start() is given a non-zero pos, it should return the iterator in the same state it was after the last ->start or ->next. This is particularly useful for interators which walk the multiple chains in a hash table, e.g. using rhashtable_walk*. See fs/gfs2/glock.c and drivers/staging/lustre/lustre/llite/vvp_dev.c A large part of achieving this is to *always* call ->next after ->show has successfully stored all of an entry in the buffer. Never just increment the index instead. Also: - always pass &m->index to ->start() and ->next(), never a temp variable - don't clear ->from when ->count is zero, as ->from is dead when ->count is zero. Some ->next functions do not increment *pos when they return NULL. To maintain compatability with this, we still need to increment m->index in one place, if ->next didn't increment it. Note that such ->next functions are buggy and should be fixed. A simple demonstration is dd if=/proc/swaps bs=1000 skip=1 Choose any block size larger than the size of /proc/swaps. This will always show the whole last line of /proc/swaps. This patch doesn't work around buggy next() functions for this case. [neilb@suse.com: ensure ->from is valid] Link: http://lkml.kernel.org/r/87601ryb8a.fsf@notabene.neil.brown.name Signed-off-by:
NeilBrown <neilb@suse.com> Acked-by: Jonathan Corbet <corbet@lwn.net> [docs] Tested-by:
Jann Horn <jannh@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Kees Cook <keescook@chromium.org> Signed-off-by:
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NeilBrown authored
This flag was introduce in 2.1.37pre1 and the only place it was tested was removed in 2.1.43pre1. The flag was never set. Let's discard it properly. Link: http://lkml.kernel.org/r/877en0hewz.fsf@notabene.neil.brown.name Signed-off-by:
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Tetsuo Handa authored
Since only dentry->d_name.len + 1 bytes out of DNAME_INLINE_LEN bytes are initialized at __d_alloc(), we can't copy the whole size unconditionally. WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff8fa27465ac50) 636f6e66696766732e746d70000000000010000000000000020000000188ffff i i i i i i i i i i i i i u u u u u u u u u u i i i i i u u u u ^ RIP: 0010:take_dentry_name_snapshot+0x28/0x50 RSP: 0018:ffffa83000f5bdf8 EFLAGS: 00010246 RAX: 0000000000000020 RBX: ffff8fa274b20550 RCX: 0000000000000002 RDX: ffffa83000f5be40 RSI: ffff8fa27465ac50 RDI: ffffa83000f5be60 RBP: ffffa83000f5bdf8 R08: ffffa83000f5be48 R09: 0000000000000001 R10: ffff8fa27465ac00 R11: ffff8fa27465acc0 R12: ffff8fa27465ac00 R13: ffff8fa27465acc0 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f79737ac8c0(0000) GS:ffffffff8fc30000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8fa274c0b000 CR3: 0000000134aa7002 CR4: 00000000000606f0 take_dentry_name_snapshot+0x28/0x50 vfs_rename+0x128/0x870 SyS_rename+0x3b2/0x3d0 entry_SYSCALL_64_fastpath+0x1a/0xa4 0xffffffffffffffff Link: http://lkml.kernel.org/r/201709131912.GBG39012.QMJLOVFSFFOOtH@I-love.SAKURA.ne.jp Signed-off-by:Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Colin Ian King authored
There are a variety of functions and variables that are local to the source and do not need to be in global scope, so make them static. Also make a couple of char arrays static const. Cleans up sparse warnings: symbol 'o2hb_heartbeat_mode_desc' was not declared. Should it be static? symbol 'o2hb_heartbeat_mode' was not declared. Should it be static? symbol 'o2hb_dependent_users' was not declared. Should it be static? symbol 'o2hb_region_dec_user' was not declared. Should it be static? symbol 'o2nm_fence_method_desc' was not declared. Should it be static? symbol 'lockdep_keys' was not declared. Should it be static? Link: http://lkml.kernel.org/r/20180628131659.12133-1-colin.king@canonical.com Signed-off-by:
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wangyan authored
Several functions have some unnecessary code, clean up these code. Link: http://lkml.kernel.org/r/5B14DF72.5020800@huawei.com Signed-off-by:
Yan Wang <wangyan122@huawei.com> Reviewed-by:
Jun Piao <piaojun@huawei.com> Reviewed-by:
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