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Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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Booting with UBI fastmap and SLUB debugging enabled results in the
following splats. The problem is that ubi_scan_fastmap() moves the
fastmap blocks from the scan_ai (allocated in scan_fast()) to the ai
allocated in ubi_attach(). This results in two problems:
- When the scan_ai is freed, aebs which were allocated from its slab
cache are still in use.
- When the other ai is being destroyed in destroy_ai(), the
arguments to kmem_cache_free() call are incorrect since aebs on its
->fastmap list were allocated with a slab cache from a differnt ai.
Fix this by making a copy of the aebs in ubi_scan_fastmap() instead of
moving them.
=============================================================================
BUG ubi_aeb_slab_cache (Not tainted): Objects remaining in ubi_aeb_slab_cache on __kmem_cache_shutdown()
-----------------------------------------------------------------------------
INFO: Slab 0xbfd2da3c objects=17 used=1 fp=0xb33d7748 flags=0x40000080
CPU: 1 PID: 118 Comm: ubiattach Tainted: G B 4.9.15 #3
[<80111910>] (unwind_backtrace) from [<8010d498>] (show_stack+0x18/0x1c)
[<8010d498>] (show_stack) from [<804a3274>] (dump_stack+0xb4/0xe0)
[<804a3274>] (dump_stack) from [<8026c47c>] (slab_err+0x78/0x88)
[<8026c47c>] (slab_err) from [<802735bc>] (__kmem_cache_shutdown+0x180/0x3e0)
[<802735bc>] (__kmem_cache_shutdown) from [<8024e13c>] (shutdown_cache+0x1c/0x60)
[<8024e13c>] (shutdown_cache) from [<8024ed64>] (kmem_cache_destroy+0x19c/0x20c)
[<8024ed64>] (kmem_cache_destroy) from [<8057cc14>] (destroy_ai+0x1dc/0x1e8)
[<8057cc14>] (destroy_ai) from [<8057f04c>] (ubi_attach+0x3f4/0x450)
[<8057f04c>] (ubi_attach) from [<8056fe70>] (ubi_attach_mtd_dev+0x60c/0xff8)
[<8056fe70>] (ubi_attach_mtd_dev) from [<80571d78>] (ctrl_cdev_ioctl+0x110/0x2b8)
[<80571d78>] (ctrl_cdev_ioctl) from [<8029c77c>] (do_vfs_ioctl+0xac/0xa00)
[<8029c77c>] (do_vfs_ioctl) from [<8029d10c>] (SyS_ioctl+0x3c/0x64)
[<8029d10c>] (SyS_ioctl) from [<80108860>] (ret_fast_syscall+0x0/0x1c)
INFO: Object 0xb33d7e88 @offset=3720
INFO: Allocated in scan_peb+0x608/0x81c age=72 cpu=1 pid=118
kmem_cache_alloc+0x3b0/0x43c
scan_peb+0x608/0x81c
ubi_attach+0x124/0x450
ubi_attach_mtd_dev+0x60c/0xff8
ctrl_cdev_ioctl+0x110/0x2b8
do_vfs_ioctl+0xac/0xa00
SyS_ioctl+0x3c/0x64
ret_fast_syscall+0x0/0x1c
kmem_cache_destroy ubi_aeb_slab_cache: Slab cache still has objects
CPU: 1 PID: 118 Comm: ubiattach Tainted: G B 4.9.15 #3
[<80111910>] (unwind_backtrace) from [<8010d498>] (show_stack+0x18/0x1c)
[<8010d498>] (show_stack) from [<804a3274>] (dump_stack+0xb4/0xe0)
[<804a3274>] (dump_stack) from [<8024ed80>] (kmem_cache_destroy+0x1b8/0x20c)
[<8024ed80>] (kmem_cache_destroy) from [<8057cc14>] (destroy_ai+0x1dc/0x1e8)
[<8057cc14>] (destroy_ai) from [<8057f04c>] (ubi_attach+0x3f4/0x450)
[<8057f04c>] (ubi_attach) from [<8056fe70>] (ubi_attach_mtd_dev+0x60c/0xff8)
[<8056fe70>] (ubi_attach_mtd_dev) from [<80571d78>] (ctrl_cdev_ioctl+0x110/0x2b8)
[<80571d78>] (ctrl_cdev_ioctl) from [<8029c77c>] (do_vfs_ioctl+0xac/0xa00)
[<8029c77c>] (do_vfs_ioctl) from [<8029d10c>] (SyS_ioctl+0x3c/0x64)
[<8029d10c>] (SyS_ioctl) from [<80108860>] (ret_fast_syscall+0x0/0x1c)
cache_from_obj: Wrong slab cache. ubi_aeb_slab_cache but object is from ubi_aeb_slab_cache
------------[ cut here ]------------
WARNING: CPU: 1 PID: 118 at mm/slab.h:354 kmem_cache_free+0x39c/0x450
Modules linked in:
CPU: 1 PID: 118 Comm: ubiattach Tainted: G B 4.9.15 #3
[<80111910>] (unwind_backtrace) from [<8010d498>] (show_stack+0x18/0x1c)
[<8010d498>] (show_stack) from [<804a3274>] (dump_stack+0xb4/0xe0)
[<804a3274>] (dump_stack) from [<80120e40>] (__warn+0xf4/0x10c)
[<80120e40>] (__warn) from [<80120f20>] (warn_slowpath_null+0x28/0x30)
[<80120f20>] (warn_slowpath_null) from [<80271fe0>] (kmem_cache_free+0x39c/0x450)
[<80271fe0>] (kmem_cache_free) from [<8057cb88>] (destroy_ai+0x150/0x1e8)
[<8057cb88>] (destroy_ai) from [<8057ef1c>] (ubi_attach+0x2c4/0x450)
[<8057ef1c>] (ubi_attach) from [<8056fe70>] (ubi_attach_mtd_dev+0x60c/0xff8)
[<8056fe70>] (ubi_attach_mtd_dev) from [<80571d78>] (ctrl_cdev_ioctl+0x110/0x2b8)
[<80571d78>] (ctrl_cdev_ioctl) from [<8029c77c>] (do_vfs_ioctl+0xac/0xa00)
[<8029c77c>] (do_vfs_ioctl) from [<8029d10c>] (SyS_ioctl+0x3c/0x64)
[<8029d10c>] (SyS_ioctl) from [<80108860>] (ret_fast_syscall+0x0/0x1c)
---[ end trace 2bd8396277fd0a0b ]---
=============================================================================
BUG ubi_aeb_slab_cache (Tainted: G B W ): page slab pointer corrupt.
-----------------------------------------------------------------------------
INFO: Allocated in scan_peb+0x608/0x81c age=104 cpu=1 pid=118
kmem_cache_alloc+0x3b0/0x43c
scan_peb+0x608/0x81c
ubi_attach+0x124/0x450
ubi_attach_mtd_dev+0x60c/0xff8
ctrl_cdev_ioctl+0x110/0x2b8
do_vfs_ioctl+0xac/0xa00
SyS_ioctl+0x3c/0x64
ret_fast_syscall+0x0/0x1c
INFO: Slab 0xbfd2da3c objects=17 used=1 fp=0xb33d7748 flags=0x40000081
INFO: Object 0xb33d7e88 @offset=3720 fp=0xb33d7da0
Redzone b33d7e80: cc cc cc cc cc cc cc cc ........
Object b33d7e88: 02 00 00 00 01 00 00 00 00 f0 ff 7f ff ff ff ff ................
Object b33d7e98: 00 00 00 00 00 00 00 00 bd 16 00 00 00 00 00 00 ................
Object b33d7ea8: 00 01 00 00 00 02 00 00 00 00 00 00 00 00 00 00 ................
Redzone b33d7eb8: cc cc cc cc ....
Padding b33d7f60: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ
CPU: 1 PID: 118 Comm: ubiattach Tainted: G B W 4.9.15 #3
[<80111910>] (unwind_backtrace) from [<8010d498>] (show_stack+0x18/0x1c)
[<8010d498>] (show_stack) from [<804a3274>] (dump_stack+0xb4/0xe0)
[<804a3274>] (dump_stack) from [<80271770>] (free_debug_processing+0x320/0x3c4)
[<80271770>] (free_debug_processing) from [<80271ad0>] (__slab_free+0x2bc/0x430)
[<80271ad0>] (__slab_free) from [<80272024>] (kmem_cache_free+0x3e0/0x450)
[<80272024>] (kmem_cache_free) from [<8057cb88>] (destroy_ai+0x150/0x1e8)
[<8057cb88>] (destroy_ai) from [<8057ef1c>] (ubi_attach+0x2c4/0x450)
[<8057ef1c>] (ubi_attach) from [<8056fe70>] (ubi_attach_mtd_dev+0x60c/0xff8)
[<8056fe70>] (ubi_attach_mtd_dev) from [<80571d78>] (ctrl_cdev_ioctl+0x110/0x2b8)
[<80571d78>] (ctrl_cdev_ioctl) from [<8029c77c>] (do_vfs_ioctl+0xac/0xa00)
[<8029c77c>] (do_vfs_ioctl) from [<8029d10c>] (SyS_ioctl+0x3c/0x64)
[<8029d10c>] (SyS_ioctl) from [<80108860>] (ret_fast_syscall+0x0/0x1c)
FIX ubi_aeb_slab_cache: Object at 0xb33d7e88 not freed
Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
When write syscall is called, every time security label is searched to
determine that file's privileges should be changed.
If LSM(Linux Security Model) is not used, this is useless.
So introduce CONFIG_UBIFS_SECURITY to disable security labels. it's default
value is "y".
Signed-off-by: Hyunchul Lee <cheol.lee@lge.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Fix permissions to allow read mtd parameter back (only for owner).
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
WARNING: vmlinux.o(.text+0x1f2a80): Section mismatch in reference from the variable __param_ops_mtd to the function .init.text:ubi_mtd_param_parse()
The function __param_ops_mtd() references
the function __init ubi_mtd_param_parse().
This is often because __param_ops_mtd lacks a __init
annotation or the annotation of ubi_mtd_param_parse is wrong.
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Pull x86 fixes from Thomas Gleixner:
"The final fixes for 4.11:
- prevent a triple fault with function graph tracing triggered via
suspend to ram
- prevent optimizing for size when function graph tracing is enabled
and the compiler does not support -mfentry
- prevent mwaitx() being called with a zero timeout as mwaitx() might
never return. Observed on the new Ryzen CPUs"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Prevent timer value 0 for MWAITX
x86/build: convert function graph '-Os' error to warning
ftrace/x86: Fix triple fault with graph tracing and suspend-to-ram
Pull scheduler fix from Thomas Gleixner:
"A single fix for a cputime accounting regression which got introduced
in the 4.11 cycle"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/cputime: Fix ksoftirqd cputime accounting regression
Newer hardware has uncovered a bug in the software implementation of
using MWAITX for the delay function. A value of 0 for the timer is meant
to indicate that a timeout will not be used to exit MWAITX. On newer
hardware this can result in MWAITX never returning, resulting in NMI
soft lockup messages being printed. On older hardware, some of the other
conditions under which MWAITX can exit masked this issue. The AMD APM
does not currently document this and will be updated.
Please refer to http://marc.info/?l=kvm&m=148950623231140 for
information regarding NMI soft lockup messages on an AMD Ryzen 1800X.
This has been root-caused as a 0 passed to MWAITX causing it to wait
indefinitely.
This change has the added benefit of avoiding the unnecessary setup of
MONITORX/MWAITX when the delay value is zero.
Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Link: http://lkml.kernel.org/r/1493156643-29366-1-git-send-email-Janakarajan.Natarajan@amd.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull iov iter fix from Al Viro.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fix a braino in ITER_PIPE iov_iter_revert()
irq_time_read() returns the irqtime minus the ksoftirqd time. This
is necessary because irq_time_read() is used to substract the IRQ time
from the sum_exec_runtime of a task. If we were to include the softirq
time of ksoftirqd, this task would substract its own CPU time everytime
it updates ksoftirqd->sum_exec_runtime which would therefore never
progress.
But this behaviour got broken by:
a499a5a14db ("sched/cputime: Increment kcpustat directly on irqtime account")
... which now includes ksoftirqd softirq time in the time returned by
irq_time_read().
This has resulted in wrong ksoftirqd cputime reported to userspace
through /proc/stat and thus "top" not showing ksoftirqd when it should
after intense networking load.
ksoftirqd->stime happens to be correct but it gets scaled down by
sum_exec_runtime through task_cputime_adjusted().
To fix this, just account the strict IRQ time in a separate counter and
use it to report the IRQ time.
Reported-and-tested-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1493129448-5356-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For pre-4.6.0 versions of GCC, which don't have '-mfentry', the
'-maccumulate-outgoing-args' option is required for function graph
tracing in order to avoid GCC bug 42109.
However, GCC ignores '-maccumulate-outgoing-args' when '-Os' is
also set.
Currently we force a build error to prevent that scenario, but that
breaks randconfigs. So change the error to a warning which also
disables CONFIG_CC_OPTIMIZE_FOR_SIZE.
Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kbuild test robot <fengguang.wu@intel.com>
Cc: kbuild-all@01.org
Link: http://lkml.kernel.org/r/20170418214429.o7fbwbmf4nqosezy@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull clk fix from Stephen Boyd:
"One odd config build fix for a recent Allwinner clock driver change
that got merged. The common code called code in another file that
wasn't always built. This just forces it on so people don't run into
this bad configuration"
* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
clk: sunxi-ng: always select CCU_GATE
Fixes: 27c0e3748e41
Tested-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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