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Christophe Leroy 21f8b2fa3c powerpc/kprobes: Ignore traps that happened in real mode
When a program check exception happens while MMU translation is
disabled, following Oops happens in kprobe_handler() in the following
code:

	} else if (*addr != BREAKPOINT_INSTRUCTION) {

  BUG: Unable to handle kernel data access on read at 0x0000e268
  Faulting instruction address: 0xc000ec34
  Oops: Kernel access of bad area, sig: 11 [#1]
  BE PAGE_SIZE=16K PREEMPT CMPC885
  Modules linked in:
  CPU: 0 PID: 429 Comm: cat Not tainted 5.6.0-rc1-s3k-dev-00824-g84195dc6c58a #3267
  NIP:  c000ec34 LR: c000ecd8 CTR: c019cab8
  REGS: ca4d3b58 TRAP: 0300   Not tainted  (5.6.0-rc1-s3k-dev-00824-g84195dc6c58a)
  MSR:  00001032 <ME,IR,DR,RI>  CR: 2a4d3c52  XER: 00000000
  DAR: 0000e268 DSISR: c0000000
  GPR00: c000b09c ca4d3c10 c66d0620 00000000 ca4d3c60 00000000 00009032 00000000
  GPR08: 00020000 00000000 c087de44 c000afe0 c66d0ad0 100d3dd6 fffffff3 00000000
  GPR16: 00000000 00000041 00000000 ca4d3d70 00000000 00000000 0000416d 00000000
  GPR24: 00000004 c53b6128 00000000 0000e268 00000000 c07c0000 c07bb6fc ca4d3c60
  NIP [c000ec34] kprobe_handler+0x128/0x290
  LR [c000ecd8] kprobe_handler+0x1cc/0x290
  Call Trace:
  [ca4d3c30] [c000b09c] program_check_exception+0xbc/0x6fc
  [ca4d3c50] [c000e43c] ret_from_except_full+0x0/0x4
  --- interrupt: 700 at 0xe268
  Instruction dump:
  913e0008 81220000 38600001 3929ffff 91220000 80010024 bb410008 7c0803a6
  38210020 4e800020 38600000 4e800020 <813b0000> 6d2a7fe0 2f8a0008 419e0154
  ---[ end trace 5b9152d4cdadd06d ]---

kprobe is not prepared to handle events in real mode and functions
running in real mode should have been blacklisted, so kprobe_handler()
can safely bail out telling 'this trap is not mine' for any trap that
happened while in real-mode.

If the trap happened with MSR_IR or MSR_DR cleared, return 0
immediately.

Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Fixes: 6cc89bad60 ("powerpc/kprobes: Invoke handlers directly")
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/424331e2006e7291a1bfe40e7f3fa58825f565e1.1582054578.git.christophe.leroy@c-s.fr
2020-03-25 12:09:51 +11:00
arch powerpc/kprobes: Ignore traps that happened in real mode 2020-03-25 12:09:51 +11:00
block block-5.6-2020-02-05 2020-02-06 06:15:23 +00:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto s390 updates for 5.6-rc2 2020-02-15 13:10:38 -08:00
Documentation powerpc/fadump: sysfs for fadump memory reservation 2020-02-19 22:46:07 +11:00
drivers powerpc/eeh: Make early EEH init pseries specific 2020-03-25 12:09:39 +11:00
fs sysfs: Wrap __compat_only_sysfs_link_entry_to_kobj function to change the symlink name 2020-02-19 21:07:09 +11:00
include sysfs: Wrap __compat_only_sysfs_link_entry_to_kobj function to change the symlink name 2020-02-19 21:07:09 +11:00
init Various fixes: 2020-02-11 16:39:18 -08:00
ipc proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
kernel Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-02-15 12:51:22 -08:00
lib Various fixes: 2020-02-11 16:39:18 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-08 13:26:41 -08:00
net NFS Client Bugfixes for Linux 5.6-rc2 2020-02-14 14:46:11 -08:00
samples Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
scripts kbuild: fix mismatch between .version and include/generated/compile.h 2020-02-11 05:18:40 +09:00
security selinux/stable-5.6 PR 20200210 2020-02-10 16:51:35 -08:00
sound ALSA: pcm: Fix double hw_free calls 2020-02-13 16:30:22 +01:00
tools selftests/powerpc: Turn off timeout setting for benchmarks, dscr, signal, tm 2020-03-25 12:09:30 +11:00
usr Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
virt KVM: Disable preemption in kvm_get_running_vcpu() 2020-02-12 12:19:35 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +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 modpost: dump missing namespaces into a single modules.nsdeps file 2019-11-11 20:10:01 +09:00
.mailmap A handful of small documentation fixes that wandered in. 2020-02-07 13:03:10 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS open: introduce openat2(2) syscall 2020-01-18 09:19:18 -05:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS MAINTAINERS: Sort entries in database for GPIO 2020-02-10 10:55:18 +01:00
Makefile Linux 5.6-rc2 2020-02-16 13:16:59 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.