- 11 Dec, 2014 40 commits
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Joe Perches authored
Emit a warning when single line string coalescing occurs. Code that uses compiler string concatenation on a single line like: printk("foo" "bar"); is generally better to read concatenated like: printk("foobar"); Signed-off-by:Joe Perches <joe@perches.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Joe Perches authored
Using BIT(foo) and BIT_ULL(bar) is more common now. Suggest using these macros over #defines with 1<<value. Add a --fix option too. Signed-off-by:
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Julius Werner authored
Checkpatch flags CamelCase identifiers in strict mode, but it has a feature to ignore parts with only two characters to allow for SI units like mV or uA. Unfortunately, not all SI units fit in two characters, and not all are lower case followed by upper case. This patch adds hardcoded detection for frequency and 1024-based size units (Hz/KHz/MHz/GHz/THz and KiB/MiB/GiB/TiB), since allowing any three character combinations might be too lenient. The list can later be expanded as needed. Signed-off-by:
Julius Werner <jwerner@chromium.org> Acked-by:
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Joe Perches authored
Peter Hurley wrote: The use of older function ptr calling style, (*fn)(), makes static analysis more error-prone; replace with modern fn() style. So make checkpatch emit a --strict test for that condition. Update the unnecessary parentheses test for dereferencing objects at the same time and create a $fix mechanism too. Signed-off-by:
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Joe Perches authored
When files are being added/moved/deleted and a patch contains an update to the MAINTAINERS file, assume it's to update the MAINTAINERS file correctly and do not emit the "does MAINTAINERS need updating?" message. Reported by many people. Signed-off-by:
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Joe Perches authored
Shift has a higher precedence that mask so warn when a mask then shift operation is done without parentheses around the mask. This test works well for a right shift, but the left shift is pretty commonly done correctly so only warn on the right shift. Signed-off-by:
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Joe Perches authored
Commit 66b47b4a ("checkpatch: look for common misspellings") made it difficult to use checkpatch via a symlink. Fix that and make a missing spelling.txt file non-fatal. Emit a warning when the spelling.txt file can not be opened. Reference: http://xkcd.com/1172/Signed-off-by:
Jani Nikula <jani.nikula@intel.com> Tested-by:
Kees Cook <keescook@chromium.org> Acked-by:
Andy Whitcroft <apw@canonical.com> Signed-off-by:
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Fabio Estevam authored
Add an 'and' to the sentence so that it looks better: WARNING: debugfs_remove(NULL) is safe and this check is probably not required Signed-off-by:
Fabio Estevam <fabio.estevam@freescale.com> Cc: Joe Perches <joe@perches.com> Signed-off-by:
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Joe Perches authored
sizeof(foo) is not a cast, allow a space after it. Signed-off-by:
Kalle Valo <kvalo@qca.qualcomm.com> Signed-off-by:
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Joe Perches authored
Using weak declarations can have unintended link defects. The __weak on the declaration causes non-weak definitions to become weak. Emit an error on its use. Signed-off-by:
Bjorn Helgaas <bhelgaas@google.com> Signed-off-by:
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Joe Perches authored
Using code like: int foo , bar; is not preferred to: int foo, bar; so emit an error on this style. Signed-off-by: -
Rasmus Villemoes authored
Return the mathematically correct answer when an argument is 0. Signed-off-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:
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Rasmus Villemoes authored
Ensure that lcm(a,b) returns the mathematically correct result, provided it fits in an unsigned long. The current version returns garbage if a*b overflows, even if the final result would fit. Signed-off-by:
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Joe Perches authored
Mark these as subscriber-only mailing lists. Signed-off-by:
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Alex Elder authored
Pranith Kumar posted a patch in which removed the "volatile" qualifier for the "logbuf_cpu" variable in vprintk_emit(). https://lkml.org/lkml/2014/11/13/894 In his patch, he used ACCESS_ONCE() for all references to that symbol to provide whatever protection was intended. There was some discussion that followed, and in the end Steven Rostedt concluded that not only was "volatile" not needed, neither was it required to use ACCESS_ONCE(). I offered an elaborate description that concluded Steven was right, and Pranith asked me to submit an alternative patch. And this is it. The basic reason "volatile" is not needed is that "logbuf_cpu" has static storage duration, and vprintk_emit() is an exported interface. This means that the value of logbuf_cpu must be read from memory the first time it is used in a particular call of vprintk_emit(). The variable's value is read only once in that function, when it's read it'll be the copy from memory (or cache). In addition, the value of "logbuf_cpu" is only ever written under protection of a spinlock. So the value that is read is the "real" value (and not an out-of-date cached one). If its value is not UINT_MAX, it is the current CPU's processor id, and it will have been last written by the running CPU. Signed-off-by:Alex Elder <elder@linaro.org> Reported-by:
Pranith Kumar <bobby.prani@gmail.com> Suggested-by:
Steven Rostedt <rostedt@goodmis.org> Reviewed-by:
Jan Kara <jack@suse.cz> Cc: Petr Mladek <pmladek@suse.cz> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Joe Perches <joe@perches.com> Signed-off-by:
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Joe Perches authored
Use #defines instead of magic values. Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jason Baron <jbaron@akamai.com> Signed-off-by:
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Joe Perches authored
Use the more common pr_warn. Coalesce formats, realign arguments. Signed-off-by:
Chris Metcalf <cmetcalf@tilera.com> Signed-off-by:
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Joe Perches authored
Coalesce the formats and align arguments. Signed-off-by:
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Joe Perches authored
Eliminate the unlikely possibility of message interleaving for early_printk/early_vprintk use. early_vprintk can be done via the %pV extension so remove this unnecessary function and change early_printk to have the equivalent vprintk code. All uses of early_printk already end with a newline so also remove the unnecessary newline from the early_printk function. Signed-off-by:
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Prarit Bhargava authored
There have been several times where I have had to rebuild a kernel to cause a panic when hitting a WARN() in the code in order to get a crash dump from a system. Sometimes this is easy to do, other times (such as in the case of a remote admin) it is not trivial to send new images to the user. A much easier method would be a switch to change the WARN() over to a panic. This makes debugging easier in that I can now test the actual image the WARN() was seen on and I do not have to engage in remote debugging. This patch adds a panic_on_warn kernel parameter and /proc/sys/kernel/panic_on_warn calls panic() in the warn_slowpath_common() path. The function will still print out the location of the warning. An example of the panic_on_warn output: The first line below is from the WARN_ON() to output the WARN_ON()'s location. After that the panic() output is displayed. WARNING: CPU: 30 PID: 11698 at /home/prarit/dummy_module/dummy-module.c:25 init_dummy+0x1f/0x30 [dummy_module]() Kernel panic - not syncing: panic_on_warn set ... CPU: 30 PID: 11698 Comm: insmod Tainted: G W OE 3.17.0+ #57 Hardware name: Intel Corporation S2600CP/S2600CP, BIOS RMLSDP.86I.00.29.D696.1311111329 11/11/2013 0000000000000000 000000008e3f87df ffff88080f093c38 ffffffff81665190 0000000000000000 ffffffff818aea3d ffff88080f093cb8 ffffffff8165e2ec ffffffff00000008 ffff88080f093cc8 ffff88080f093c68 000000008e3f87df Call Trace: [<ffffffff81665190>] dump_stack+0x46/0x58 [<ffffffff8165e2ec>] panic+0xd0/0x204 [<ffffffffa038e05f>] ? init_dummy+0x1f/0x30 [dummy_module] [<ffffffff81076b90>] warn_slowpath_common+0xd0/0xd0 [<ffffffffa038e040>] ? dummy_greetings+0x40/0x40 [dummy_module] [<ffffffff81076c8a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa038e05f>] init_dummy+0x1f/0x30 [dummy_module] [<ffffffff81002144>] do_one_initcall+0xd4/0x210 [<ffffffff811b52c2>] ? __vunmap+0xc2/0x110 [<ffffffff810f8889>] load_module+0x16a9/0x1b30 [<ffffffff810f3d30>] ? store_uevent+0x70/0x70 [<ffffffff810f49b9>] ? copy_module_from_fd.isra.44+0x129/0x180 [<ffffffff810f8ec6>] SyS_finit_module+0xa6/0xd0 [<ffffffff8166cf29>] system_call_fastpath+0x12/0x17 Successfully tested by me. hpa said: There is another very valid use for this: many operators would rather a machine shuts down than being potentially compromised either functionally or security-wise. Signed-off-by:Prarit Bhargava <prarit@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Acked-by:
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Fabian Frederick <fabf@skynet.be> Signed-off-by:
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Yann Droneaud authored
Macro get_unused_fd() is used to allocate a file descriptor with default flags. Those default flags (0) don't enable close-on-exec. This can be seen as an unsafe default: in most case close-on-exec should be enabled to not leak file descriptor across exec(). It would be better to have a "safer" default set of flags, eg. O_CLOEXEC must be used to enable close-on-exec. Instead this patch removes get_unused_fd() so that out of tree modules won't be affect by a runtime behavor change which might introduce other kind of bugs: it's better to catch the change at build time, making it easier to fix. Removing the macro will also promote use of get_unused_fd_flags() (or anon_inode_getfd()) with flags provided by userspace. Or, if flags cannot be given by userspace, with flags set to O_CLOEXEC by default. Signed-off-by:
Yann Droneaud <ydroneaud@opteya.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Yann Droneaud authored
This patch replaces calls to get_unused_fd() with equivalent call to get_unused_fd_flags(0) to preserve current behavor for existing code. In a further patch, get_unused_fd() will be removed so that new code start using get_unused_fd_flags(), with the hope O_CLOEXEC could be used, either by default or choosen by userspace. Signed-off-by:
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Yann Droneaud authored
This patch replaces calls to get_unused_fd() with equivalent call to get_unused_fd_flags(0) to preserve current behavor for existing code. In a further patch, get_unused_fd() will be removed so that new code start using get_unused_fd_flags(), with the hope O_CLOEXEC could be used, either by default or choosen by userspace. Signed-off-by:
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Yann Droneaud authored
This patch replaces calls to get_unused_fd() with equivalent call to get_unused_fd_flags(0) to preserve current behavor for existing code. In a further patch, get_unused_fd() will be removed so that new code start using get_unused_fd_flags(), with the hope O_CLOEXEC could be used, either by default or choosen by userspace. Signed-off-by:
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Yann Droneaud authored
This patch replaces calls to get_unused_fd() with equivalent call to get_unused_fd_flags(0) to preserve current behavor for existing code. In a further patch, get_unused_fd() will be removed so that new code start using get_unused_fd_flags(), with the hope O_CLOEXEC could be used, either by default or choosen by userspace. Signed-off-by:
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Oleg Nesterov authored
Now that forget_original_parent() uses ->ptrace_entry for EXIT_DEAD tasks, we can simply pass "dead_children" list to exit_ptrace() and remove another release_task() loop. Plus this way we do not need to drop and reacquire tasklist_lock. Also shift the list_empty(ptraced) check, if we want this optimization it makes sense to eliminate the function call altogether. 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:
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Oleg Nesterov authored
1. Now that reparent_leader() doesn't abuse ->sibling we can shift list_move_tail() from reparent_leader() to forget_original_parent() and turn it into a single list_splice_tail_init(). This also makes BUG_ON(!list_empty()) and list_for_each_entry_safe() unnecessary. 2. This also allows to shift the same_thread_group() check, it looks a bit more clear in the caller. Signed-off-by:
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Oleg Nesterov authored
1. Cosmetic, but "if (t->parent == father)" looks a bit confusing. We need to change t->parent if and only if t is not traced. 2. If we actually want this BUG_ON() to ensure that parent/ptrace match each other, then we should also take ptrace_reparented() case into account too. 3. Change this code to use for_each_thread() instead of deprecated while_each_thread(). [dan.carpenter@oracle.com: silence a bogus static checker warning] Signed-off-by:
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Oleg Nesterov authored
reparent_leader() reuses ->sibling as a list node to add an EXIT_DEAD task into dead_children list we are going to release. This obviously removes the dead task from its real_parent->children list and this is even good; the parent can do nothing with the EXIT_DEAD reparented zombie, it only makes do_wait() slower. But, this also means that it can not be reparented once again, so if its new parent dies too nobody will update ->parent/real_parent, they can point to the freed memory even before release_task() we are going to call, this breaks the code which relies on pid_alive() to access ->real_parent/parent. Fortunately this is mostly theoretical, this can only happen if init or PR_SET_CHILD_SUBREAPER process ignores SIGCHLD and the new parent sub-thread exits right after we drop tasklist_lock. Change this code to use ->ptrace_entry instead, we know that the child is not traced so nobody can ever use this member. This also allows to unify this logic with exit_ptrace(), see the next changes. Note: we really need to change release_task() to nullify real_parent/ parent/group_leader pointers, but we need to change the current users first somehow. And it would be better to reap this zombie immediately but release_task_locked() we need is complicated by proc_flush_task(). Signed-off-by:
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Oleg Nesterov authored
rcu_read_lock() can not protect p->real_parent if release_task(p) was already called, change sched_show_task() to check pis_alive() like other users do. Note: we need some helpers to cleanup the code like this. And it seems that that the usage of cpu_curr(cpu) in dump_cpu_task() is not safe too. Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Roland McGrath <roland@hack.frob.com> Signed-off-by:
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Oleg Nesterov authored
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:
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Oleg Nesterov authored
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:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by:
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Oleg Nesterov authored
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:
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Oleg Nesterov authored
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:
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Nicolas Dichtel authored
Better to use existing macro that rewriting them. Signed-off-by:
Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by:
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Debabrata Banerjee authored
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:
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Nicolas Dichtel authored
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:
David S. Miller <davem@davemloft.net> Cc: Thierry Herbelot <thierry.herbelot@6wind.com>. Acked-by:
"Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by:
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Johannes Weiner authored
Now that the external page_cgroup data structure and its lookup is gone, let the generic bad_page() check for page->mem_cgroup sanity. Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Acked-by:
Michal Hocko <mhocko@suse.cz> Acked-by:
Vladimir Davydov <vdavydov@parallels.com> Acked-by:
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Johannes Weiner authored
Now that the external page_cgroup data structure and its lookup is gone, the only code remaining in there is swap slot accounting. Rename it and move the conditional compilation into mm/Makefile. Signed-off-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Tejun Heo <tj@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by:
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Johannes Weiner authored
Memory cgroups used to have 5 per-page pointers. To allow users to disable that amount of overhead during runtime, those pointers were allocated in a separate array, with a translation layer between them and struct page. There is now only one page pointer remaining: the memcg pointer, that indicates which cgroup the page is associated with when charged. The complexity of runtime allocation and the runtime translation overhead is no longer justified to save that *potential* 0.19% of memory. With CONFIG_SLUB, page->mem_cgroup actually sits in the doubleword padding after the page->private member and doesn't even increase struct page, and then this patch actually saves space. Remaining users that care can still compile their kernels without CONFIG_MEMCG. text data bss dec hex filename 8828345 1725264 983040 11536649 b00909 vmlinux.old 8827425 1725264 966656 11519345 afc571 vmlinux.new [mhocko@suse.cz: update Documentation/cgroups/memory.txt] Signed-off-by:Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by:
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