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Stafford Horne 57b8e277c3 openrisc: Fix oops caused when dumping stack
When dumping a stack with 'cat /proc/#/stack' the kernel would oops.
For example:

    # cat /proc/690/stack
    Unable to handle kernel access
     at virtual address 0x7fc60f58

    Oops#: 0000
    CPU #: 0
       PC: c00097fc    SR: 0000807f    SP: d6f09b9c
    GPR00: 00000000 GPR01: d6f09b9c GPR02: d6f09bb8 GPR03: d6f09bc4
    GPR04: 7fc60f5c GPR05: c00099b4 GPR06: 00000000 GPR07: d6f09ba3
    GPR08: ffffff00 GPR09: c0009804 GPR10: d6f08000 GPR11: 00000000
    GPR12: ffffe000 GPR13: dbb86000 GPR14: 00000001 GPR15: dbb86250
    GPR16: 7fc60f63 GPR17: 00000f5c GPR18: d6f09bc4 GPR19: 00000000
    GPR20: c00099b4 GPR21: ffffffc0 GPR22: 00000000 GPR23: 00000000
    GPR24: 00000001 GPR25: 000002c6 GPR26: d78b6850 GPR27: 00000001
    GPR28: 00000000 GPR29: dbb86000 GPR30: ffffffff GPR31: dbb862fc
      RES: 00000000 oGPR11: ffffffff
    Process cat (pid: 702, stackpage=d79d6000)

    Stack:
    Call trace:
    [<598977f2>] save_stack_trace_tsk+0x40/0x74
    [<95063f0e>] stack_trace_save_tsk+0x44/0x58
    [<b557bfdd>] proc_pid_stack+0xd0/0x13c
    [<a2df8eda>] proc_single_show+0x6c/0xf0
    [<e5a737b7>] seq_read+0x1b4/0x688
    [<2d6c7480>] do_iter_read+0x208/0x248
    [<2182a2fb>] vfs_readv+0x64/0x90

This was caused by the stack trace code in save_stack_trace_tsk using
the wrong stack pointer.  It was using the user stack pointer instead of
the kernel stack pointer.  Fix this by using the right stack.

Also for good measure we add try_get_task_stack/put_task_stack to ensure
the task is not lost while we are walking it's stack.

Fixes: eecac38b04 ("openrisc: support framepointers and STACKTRACE_SUPPORT")
Signed-off-by: Stafford Horne <shorne@gmail.com>
2020-08-04 10:59:45 +09:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-01 16:47:24 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch openrisc: Fix oops caused when dumping stack 2020-08-04 10:59:45 +09:00
block block-5.8-2020-07-10 2020-07-10 09:55:46 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto keys: asymmetric: fix error return code in software_key_query() 2020-07-15 15:49:04 -07:00
drivers Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-01 16:47:24 -07:00
fs io_uring-5.8-2020-07-30 2020-07-30 09:47:07 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-01 16:47:24 -07:00
init init: Align init_task to avoid conflict with MUTEX_FLAGS 2020-08-04 10:59:45 +09:00
ipc mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-01 16:47:24 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-01 16:47:24 -07:00
mm khugepaged: fix null-pointer dereference due to race 2020-07-24 12:42:41 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-01 16:47:24 -07:00
samples samples/vfs: avoid warning in statx override 2020-07-03 16:15:25 -07:00
scripts kbuild: remove redundant FORCE definition in scripts/Makefile.modpost 2020-08-02 23:09:16 +09:00
security integrity/ima: switch to using __kernel_read 2020-07-08 08:27:57 +02:00
sound sound fixes for 5.8-final or -rc8 2020-07-31 09:17:24 -07:00
tools Bugfixes and strengthening the validity checks on inputs from new userspace APIs. 2020-08-02 10:41:00 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
virt kvm: use more precise cast and do not drop __user 2020-07-02 05:39:31 -04:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Do not track `defconfig` from `make savedefconfig` 2020-07-05 16:15:46 +09:00
.mailmap mailmap: add entry for Mike Rapoport 2020-07-24 12:42:41 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mailmap: change email for Ricardo Ribalda 2020-05-25 18:59:59 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-01 16:47:24 -07:00
Makefile Linux 5.8 2020-08-02 14:21:45 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.