- 06 Jun, 2014 40 commits
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Srivatsa S. Bhat authored
There is a longstanding problem related to CPU hotplug which causes IPIs to be delivered to offline CPUs, and the smp-call-function IPI handler code prints out a warning whenever this is detected. Every once in a while this (usually harmless) warning gets reported on LKML, but so far it has not been completely fixed. Usually the solution involves finding out the IPI sender and fixing it by adding appropriate synchronization with CPU hotplug. However, while going through one such internal bug reports, I found that there is a significant bug in the receiver side itself (more specifically, in stop-machine) that can lead to this problem even when the sender code is perfectly fine. This patchset fixes that synchronization problem in the CPU hotplug stop-machine code. Patch 1 adds some additional debug code to the smp-call-function framework, to help debug such issues easily. Patch 2 modifies the stop-machine code to ensure that any IPIs that were sent while the target CPU was online, would be noticed and handled by that CPU without fail before it goes offline. Thus, this avoids scenarios where IPIs are received on offline CPUs (as long as the sender uses proper hotplug synchronization). In fact, I debugged the problem by using Patch 1, and found that the payload of the IPI was always the block layer's trigger_softirq() function. But I was not able to find anything wrong with the block layer code. That's when I started looking at the stop-machine code and realized that there is a race-window which makes the IPI _receiver_ the culprit, not the sender. Patch 2 fixes that race and hence this should put an end to most of the hard-to-debug IPI-to-offline-CPU issues. This patch (of 2): Today the smp-call-function code just prints a warning if we get an IPI on an offline CPU. This info is sufficient to let us know that something went wrong, but often it is very hard to debug exactly who sent the IPI and why, from this info alone. In most cases, we get the warning about the IPI to an offline CPU, immediately after the CPU going offline comes out of the stop-machine phase and reenables interrupts. Since all online CPUs participate in stop-machine, the information regarding the sender of the IPI is already lost by the time we exit the stop-machine loop. So even if we dump the stack on each CPU at this point, we won't find anything useful since all of them will show the stack-trace of the stopper thread. So we need a better way to figure out who sent the IPI and why. To achieve this, when we detect an IPI targeted to an offline CPU, loop through the call-single-data linked list and print out the payload (i.e., the name of the function which was supposed to be executed by the target CPU). This would give us an insight as to who might have sent the IPI and help us debug this further. [akpm@linux-foundation.org: correctly suppress warning output on second and later occurrences] Signed-off-by:
Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mike Galbraith <mgalbraith@suse.de> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Fabian Frederick authored
Static values are automatically initialized to NULL. Signed-off-by:
Fabian Frederick <fabf@skynet.be> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by:
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Fabian Frederick authored
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Oleg Nesterov authored
Now that we have kernel_sigaction() we can change wait_for_helper() to use it and cleans up the code a bit. Signed-off-by:
Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Richard Weinberger <richard@nod.at> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by:
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Oleg Nesterov authored
Now that allow_signal() is really trivial we can unify it with disallow_signal(). Add the new helper, kernel_sigaction(), and reimplement allow_signal/disallow_signal as a trivial wrappers. This saves one EXPORT_SYMBOL() and the new helper can have more users. Signed-off-by:
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Oleg Nesterov authored
disallow_signal() simply sets SIG_IGN, this is not enough and recalc_sigpending() is simply pointless because in can never change the state of TIF_SIGPENDING. If we ignore a signal, we also need to do flush_sigqueue_mask() for the case when this signal is pending, this way recalc_sigpending() can actually clear TIF_SIGPENDING and we do not "leak" the allocated siginfo's. Signed-off-by:
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Oleg Nesterov authored
allow_signal() does sigdelset(current->blocked) due to historic reason, previously it could be called by a daemonize()'ed kthread, and daemonize() played with current->blocked. Now that daemonize() has gone away we can remove sigdelset() and recalc_sigpending(). If a user really wants to unblock a signal, it must use sigprocmask() or set_current_block() explicitely. Signed-off-by:
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Oleg Nesterov authored
jffs2_garbage_collect_thread() does disallow_signal(SIGHUP) around jffs2_garbage_collect_pass() and the comment says "We don't want SIGHUP to interrupt us". But disallow_signal() can't ensure that jffs2_garbage_collect_pass() won't be interrupted by SIGHUP, the problem is that SIGHUP can be already pending when disallow_signal() is called, and in this case any interruptible sleep won't block. Note: this is in fact because disallow_signal() is buggy and should be fixed, see the next changes. But there is another reason why disallow_signal() is wrong: SIG_IGN set by disallow_signal() silently discards any SIGHUP which can be sent before the next allow_signal(SIGHUP). Change this code to use sigprocmask(SIG_UNBLOCK/SIG_BLOCK, SIGHUP). This even matches the old (and wrong) semantics allow/disallow had when this logic was written. Signed-off-by:
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Oleg Nesterov authored
Move the declaration/definition of allow_signal/disallow_signal to signal.h/signal.c. The new place is more logical and allows to use the static helpers in signal.c (see the next changes). While at it, make them return void and remove the valid_signal() check. Nobody checks the returned value, and in-kernel users must not pass the wrong signal number. Signed-off-by:
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Oleg Nesterov authored
The usage of "task_struct *t" and "current" in do_sigaction() looks really annoying and chaotic. Initially "t" is used as a cached value of current but not consistently, then it is reused as a loop variable and we have to use "current" again. Clean up this mess and also convert the code to use for_each_thread(). Signed-off-by:
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Oleg Nesterov authored
"rm_from_queue_full" looks ugly and misleading, especially now that rm_from_queue() has gone away. Rename it to flush_sigqueue_mask(), this matches flush_sigqueue() we already have. Also remove the obsolete comment which explains the difference with rm_from_queue() we already killed. Signed-off-by:
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Oleg Nesterov authored
rm_from_queue() doesn't make sense. The only caller, prepare_signal(), can use rm_from_queue_full() with the same effect. While at it, change prepare_signal() to use for_each_thread() instead of do/while_each_thread. Signed-off-by:
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Oleg Nesterov authored
Cosmetic, but siginitset(0) looks a bit strange, sigemptyset() is what do_sigtimedwait() needs. Signed-off-by:
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Oleg Nesterov authored
It has no users and it doesn't look useful. I do not know why/when it was introduced, I can't even find any user in the git history. Signed-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Richard Weinberger <richard@nod.at> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by:
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Oleg Nesterov authored
__wake_up_bit() checks waitqueue_active() and thus the caller needs mb() as wake_up_bit() documents, fix task_clear_jobctl_trapping(). Signed-off-by:
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Matthew Dempsky authored
When tracing a process in another pid namespace, it's important for fork event messages to contain the child's pid as seen from the tracer's pid namespace, not the parent's. Otherwise, the tracer won't be able to correlate the fork event with later SIGTRAP signals it receives from the child. We still risk a race condition if a ptracer from a different pid namespace attaches after we compute the pid_t value. However, sending a bogus fork event message in this unlikely scenario is still a vast improvement over the status quo where we always send bogus fork event messages to debuggers in a different pid namespace than the forking process. Signed-off-by:
Matthew Dempsky <mdempsky@chromium.org> Acked-by:
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Alexey Dobriyan authored
Examples introducing neccesity of RMB+WMP pair reads as A=3 READ B www rrrrrr B=4 READ A Note the opposite order of reads vs writes. But the first example without barriers reads as A=3 READ A B=4 READ B There are 4 outcomes in the first example. But if someone new to the concept tries to insert barriers like this: A=3 READ A www rrrrrr B=4 READ B he will still get all 4 possible outcomes, because "READ A" is first. All this can be utterly confusing because barrier pair seems to be superfluous. In short, fixup first example to match latter examples with barriers. Signed-off-by:Alexey Dobriyan <adobriyan@gmail.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by:
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Fabian Frederick authored
Linked article in seq_file.txt still uses create_proc_entry which was removed in commit 80e928f7 ("proc: Kill create_proc_entry()"). This patch adds information for kernel 3.10 and above Signed-off-by:
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Jacob Keller authored
Update the SubmittingPatches process to include howto about the new 'Fixes:' tag to be used when a patch fixes an issue in a previous commit (found by git-bisect for example). Signed-off-by:
Jacob Keller <jacob.e.keller@intel.com> Tested-by:
Aaron Brown <aaron.f.brown@intel.com> Signed-off-by:
Jeff Kirsher <jeffrey.t.kirsher@intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by:
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Manuel Schölling authored
Initializations like 'char *foo = "bar"' will create two variables: a static string and a pointer (foo) to that static string. Instead 'char foo[] = "bar"' will declare a single variable and will end up in shorter assembly (according to Jeff Garzik on the KernelJanitor's TODO list). Signed-off-by:
Manuel Schölling <manuel.schoelling@gmx.de> Acked-by:
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by:
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Conrad Meyer authored
Add structure for parsed BPB information, struct fat_bios_param_block, and move all of the deserialization and validation logic from fat_fill_super() into fat_read_bpb(). Add a 'dos1xfloppy' mount option to infer DOS 2.x BIOS Parameter Block defaults from block device geometry for ancient floppies and floppy images, as a fall-back from the default BPB parsing logic. When fat_read_bpb() finds an invalid FAT filesystem and dos1xfloppy is set, fall back to fat_read_static_bpb(). fat_read_static_bpb() validates that the entire BPB is zero, and that the floppy has a DOS-style 8086 code bootstrapping header. Then it fills in default BPB values from media size and a table.[0] Media size is assumed to be static for archaic FAT volumes. See also: [1]. Fixes kernel.org bug #42617. [0]: https://en.wikipedia.org/wiki/File_Allocation_Table#Exceptions [1]: http://www.win.tue.nl/~aeb/linux/fs/fat/fat-1.html [hirofumi@mail.parknet.co.jp: fix missed error code] Signed-off-by:
Conrad Meyer <cse.cem@gmail.com> Acked-by:
Alan Cox <alan@linux.intel.com> Signed-off-by:
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Fabian Frederick authored
This patch applies a suggestion by Mikulas Patocka asking to increase all pr_warn without commented ones to pr_err Signed-off-by:
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Fabian Frederick authored
Normalize function display fx() using __func__ Signed-off-by:
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Fabian Frederick authored
Also remove redundant level names (warning:...) Signed-off-by:
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Fabian Frederick authored
No level printk in hptfs_error converted to pr_err (others to pr_warn or pr_info) This patch also fixes if/then/else checkpatch warnings Signed-off-by:
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Fabian Frederick authored
err is used in ufs_new_fragments (ufs_add_fragments only callsite) not in ufs_add_fragments. Signed-off-by:
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Christian Kujau authored
Commit a99b7069 ("hfsplus: Fix undefined __divdi3 in hfsplus_init_header_node()") introduced do_div() to xattr.c and the warning below too. As Geert remarked: "tmp" is "loff_t" which is "__kernel_loff_t", which is "long long", i.e. signed, while include/asm-generic/div64.h compares its type with "uint64_t". As inode sizes are positive, it should be safe to change the type of "tmp" to "u64". In file included from arch/powerpc/include/asm/div64.h:1:0, from include/linux/kernel.h:124, from include/asm-generic/bug.h:13, from arch/powerpc/include/asm/bug.h:127, from include/linux/bug.h:4, from include/linux/thread_info.h:11, from include/asm-generic/preempt.h:4, from arch/powerpc/include/generated/asm/preempt.h:1, from include/linux/preempt.h:18, from include/linux/spinlock.h:50, from include/linux/wait.h:8, from include/linux/fs.h:6, from fs/hfsplus/hfsplus_fs.h:19, from fs/hfsplus/xattr.c:9: fs/hfsplus/xattr.c: In function 'hfsplus_init_header_node': include/asm-generic/div64.h:43:28: warning: comparison of distinct pointer types lacks a cast [enabled by default] (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \ ^ fs/hfsplus/xattr.c:86:2: note: in expansion of macro 'do_div' do_div(tmp, node_size); ^ Signed-off-by:
Christian Kujau <lists@nerdbynature.de> Signed-off-by:
Sergei Antonov <saproj@gmail.com> Signed-off-by:
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Fabian Frederick authored
Signed-off-by:
Vyacheslav Dubeyko <slava@dubeyko.com> Signed-off-by:
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Sergei Antonov authored
Some function declarations in hfsplus_fs.h were with argument names, some without, and some were mixed. This patch adds argument names everywhere, sorts function in order they go in .c files, and moves hfs_part_find() to a proper section. Auto-formatting and sorting was done with: cfunctions *.c | indent -linux | sed "s| \* | \*|" Signed-off-by:
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Fabian Frederick authored
Replace while blocksize;shift by ilog2 Signed-off-by:
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Sergei Antonov authored
Zero newly allocated extents in the catalog tree if volume attributes tell us to. Not doing so we risk getting the "unused node is not erased" error. See kHFSUnusedNodeFix flag in Apple's source code for reference. There was a previous commit clearing the node when it is freed: commit 899bed05 ("hfsplus: fix issue with unzeroed unused b-tree nodes"). But it did not handle newly allocated extents (this patch fixes it). And it zeroed nodes in all trees unconditionally which is an overkill. This patch adds a condition and also switches to 'tree->node_size' as a simpler method of getting the length to zero. Signed-off-by:
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Fabian Frederick authored
Also add * before function comments (it was not detected by kernel-doc) Signed-off-by:
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Fabian Frederick authored
Replace seq_printf where possible Signed-off-by:
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Fabian Frederick authored
Also fixes some pr_ formats Signed-off-by:
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Sergei Antonov authored
hfsplus_readdir() incorrectly returned DT_REG for symbolic links and special files. Return DT_REG, DT_LNK, DT_FIFO, DT_CHR, DT_BLK, DT_SOCK, or DT_UNKNOWN according to mode field in catalog record. Programs relying on information from readdir will now work correctly with HFS+. Signed-off-by:
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Hin-Tak Leung authored
The directory/file catalog b-tree equivalent, hfsplus_build_key_uni(), is used by hfsplus_find_cat() for internal referencing between catalog records. There is no corresponding usage for attributes - attribute records do not refer to one another. Signed-off-by:
Hin-Tak Leung <htl10@users.sourceforge.net> Cc: Sougata Santra <sougata@tuxera.com> Cc: Anton Altaparmakov <anton@tuxera.com> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by:
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Hin-Tak Leung authored
HFSPLUS_ATTR_MAX_STRLEN (=127) is the limit of attribute names for the number of unicode character (UTF-16BE) storable in the HFS+ file system. Almost all the current usage of it is wrong, in relation to NLS to on-disk conversion. Except for one use calling hfsplus_asc2uni (which should stay the same) and its uses in calling hfsplus_uni2asc (which was corrected in the earlier patch in this series concerning usage of hfsplus_uni2asc), all the other uses are of the forms: - char buffer[size] - bound check: "if (namespace_adjusted_input_length > size) return failure;" Conversion between on-disk unicode representation and NLS char strings (in whichever direction) always needs to accommodate the worst-case NLS conversion, so all char buffers of that size need to have a NLS_MAX_CHARSET_SIZE x . The bound checks are all wrong, since they compare nls_length derived from strlen() to a unicode length limit. It turns out that all the bound-checks do is to protect hfsplus_asc2uni(), which can fail if the input is too large. There is only one usage of it as far as attributes are concerned, in hfsplus_attr_build_key(). It is in turn used by hfsplus_find_attr(), hfsplus_create_attr(), hfsplus_delete_attr(). Thus making sure that errors from hfsplus_asc2uni() is caught in hfsplus_attr_build_key() and propagated is sufficient to replace all the bound checks. Unpropagated errors from hfsplus_asc2uni() in the file catalog code was addressed recently in an independent patch "hfsplus: fix longname handling" by Sougata Santra. Before this patch, trying to set a 55 CJK character (in a UTF-8 locale, > 127/3=42) attribute plus user prefix fails with: $ setfattr -n user.`cat testing-string` -v `cat testing-string` \ testing-string setfattr: testing-string: Operation not supported and retrieving a stored long attributes is particular ugly(!): find /mnt/* -type f -exec getfattr -d {} \; getfattr: /mnt/testing-string: Input/output error with console log: [268008.389781] hfsplus: unicode conversion failed After the patch, both of the above works. FYI, the test attribute string is prepared with: echo -e -n \ "\xe9\x80\x99\xe6\x98\xaf\xe4\xb8\x80\xe5\x80\x8b\xe9\x9d\x9e\xe5" \ "\xb8\xb8\xe6\xbc\xab\xe9\x95\xb7\xe8\x80\x8c\xe6\xa5\xb5\xe5\x85" \ "\xb6\xe4\xb9\x8f\xe5\x91\xb3\xe5\x92\x8c\xe7\x9b\xb8\xe7\x95\xb6" \ "\xe7\x84\xa1\xe8\xb6\xa3\xe3\x80\x81\xe4\xbb\xa5\xe5\x8f\x8a\xe7" \ "\x84\xa1\xe7\x94\xa8\xe7\x9a\x84\xe3\x80\x81\xe5\x86\x8d\xe5\x8a" \ "\xa0\xe4\xb8\x8a\xe6\xaf\xab\xe7\x84\xa1\xe6\x84\x8f\xe7\xbe\xa9" \ "\xe7\x9a\x84\xe6\x93\xb4\xe5\xb1\x95\xe5\xb1\xac\xe6\x80\xa7\xef" \ "\xbc\x8c\xe8\x80\x8c\xe5\x85\xb6\xe5\x94\xaf\xe4\xb8\x80\xe5\x89" \ "\xb5\xe5\xbb\xba\xe7\x9b\xae\xe7\x9a\x84\xe5\x83\x85\xe6\x98\xaf" \ "\xe7\x82\xba\xe4\xba\x86\xe6\xb8\xac\xe8\xa9\xa6\xe4\xbd\x9c\xe7" \ "\x94\xa8\xe3\x80\x82" | tr -d ' ' (= "pointlessly long attribute for testing", elaborate Chinese in UTF-8 enoding). However, it is not possible to set double the size (110 + 5 is still under 127) in a UTF-8 locale: $setfattr -n user.`cat testing-string testing-string` -v \ `cat testing-string testing-string` testing-string setfattr: testing-string: Numerical result out of range 110 CJK char in UTF-8 is 330 bytes - the generic get/set attribute system call code in linux/fs/xattr.c imposes a 255 byte limit. One can use a combination of iconv to encode content, changing terminal locale for viewing, and an nls=cp932/cp936/cp949/cp950 mount option to fully use 127-unicode attribute in a double-byte locale. Also, as an additional information, it is possible to (mis-)use unicode half-width/full-width forms (U+FFxx) to write attributes which looks like english but not actually ascii. Thanks Anton Altaparmakov for reviewing the earlier ideas behind this change. [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build] Signed-off-by: -
Hin-Tak Leung authored
This is a series of 3 patches which corrects issues in HFS+ concerning the use of non-english file names and attributes. Names and attributes are stored internally as UTF-16 units up to a fixed maximum size, and convert to and from user-representation by NLS. The code incorrectly assume that NLS string lengths are equal to unicode lengths, which is only true for English ascii usage. This patch (of 3): The HFS Plus Volume Format specification (TN1150) states that file names are stored internally as a maximum of 255 unicode characters, as defined by The Unicode Standard, Version 2.0 [Unicode, Inc. ISBN 0-201-48345-9]. File names are converted by the NLS system on Linux before presented to the user. 255 CJK characters converts to UTF-8 with 1 unicode character to up to 3 bytes, and to GB18030 with 1 unicode character to up to 4 bytes. Thus, trying in a UTF-8 locale to list files with names of more than 85 CJK characters results in: $ ls /mnt ls: reading directory /mnt: File name too long The receiving buffer to hfsplus_uni2asc() needs to be 255 x NLS_MAX_CHARSET_SIZE bytes, not 255 bytes as the code has always been. Similar consideration applies to attributes, which are stored internally as a maximum of 127 UTF-16BE units. See XNU source for an up-to-date reference on attributes. Strictly speaking, the maximum value of NLS_MAX_CHARSET_SIZE = 6 is not attainable in the case of conversion to UTF-8, as going beyond 3 bytes requires the use of surrogate pairs, i.e. consuming two input units. Thanks Anton Altaparmakov for reviewing an earlier version of this change. This patch fixes all callers of hfsplus_uni2asc(), and also enables the use of long non-English file names in HFS+. The getting and setting, and general usage of long non-English attributes requires further forthcoming work, in the following patches of this series. [akpm@linux-foundation.org: fix build] Signed-off-by:Anton Altaparmakov <anton@tuxera.com> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Sougata Santra <sougata@tuxera.com> Signed-off-by:
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Fabian Frederick authored
Replace all function names by __func__ in pr_foo() Signed-off-by:
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Fabian Frederick authored
- Add pr_fmt based on module name. - Remove Coda: coda: from pr_foo() Signed-off-by:
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