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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.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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Pull cifs fixes from Steve French:
"Eight cifs/smb3 fixes, including three for stable.
Three are DFS related fixes, and two to fix problems pointed out by
static checkers"
* tag '5.14-rc1-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: do not share tcp sessions of dfs connections
SMB3.1.1: fix mount failure to some servers when compression enabled
cifs: added WARN_ON for all the count decrements
cifs: fix missing null session check in mount
cifs: handle reconnect of tcon when there is no cached dfs referral
cifs: fix the out of range assignment to bit fields in parse_server_interfaces
cifs: Do not use the original cruid when following DFS links for multiuser mounts
cifs: use the expiry output of dns_query to schedule next resolution
Pull kunit fixes from Shuah Khan:
"Fixes to kunit tool and documentation:
- fix asserts on older python versions
- fixes to misleading error messages when TAP header format is
incorrect or when file is missing
- documentation fix: drop obsolete information about uml_abort
coverage
- remove unnecessary annotations"
* tag 'linux-kselftest-kunit-fixes-5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
kunit: tool: Assert the version requirement
kunit: tool: remove unnecessary "annotations" import
Documentation: kunit: drop obsolete note about uml_abort for coverage
kunit: tool: Fix error messages for cases of no tests and wrong TAP header
Make sure that we do not share tcp sessions of dfs mounts when
mounting regular shares that connect to same server. DFS connections
rely on a single instance of tcp in order to do failover properly in
cifs_reconnect().
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull kselftest fix from Shuah Khan:
"A fix to memory-hotplug hot-remove test to stop spamming logs with
dump_page() entries and slowing the system down to a crawl"
* tag 'linux-kselftest-fixes-5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
selftests: memory-hotplug: avoid spamming logs with dump_page(), ratio limit hot-remove error test
Commit 87c9c1631788 ("kunit: tool: add support for QEMU") on the 'next'
tree adds 'from __future__ import annotations' in 'kunit_kernel.py'.
Because it is supported on only >=3.7 Python, people using older Python
will get below error:
Traceback (most recent call last):
File "./tools/testing/kunit/kunit.py", line 20, in <module>
import kunit_kernel
File "/home/sjpark/linux/tools/testing/kunit/kunit_kernel.py", line 9
from __future__ import annotations
^
SyntaxError: future feature annotations is not defined
This commit adds a version assertion in 'kunit.py', so that people get
more explicit error message like below:
Traceback (most recent call last):
File "./tools/testing/kunit/kunit.py", line 15, in <module>
assert sys.version_info >= (3, 7), "Python version is too old"
AssertionError: Python version is too old
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Acked-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
When sending the compression context to some servers, they rejected
the SMB3.1.1 negotiate protocol because they expect the compression
context to have a data length of a multiple of 8.
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull tracing fix from Steven Rostedt:
"Fix the histogram logic from possibly crashing the kernel
Working on the histogram code, I found that if you dereference a char
pointer in a trace event that happens to point to user space, it can
crash the kernel, as it does no checks of that pointer. I have code
coming that will do this better, so just remove this ability to treat
character pointers in trace events as stings in the histogram"
* tag 'trace-v5.14-5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Do not reference char * as a string in histograms
While the offline memory test obey ratio limit, the same test with
error injection does not and tries to offline all the hotpluggable
memory, spamming system logs with hundreds of thousands of dump_page()
entries, slowing system down (to the point the test itself timesout and
gets terminated) and excessive fs occupation:
...
[ 9784.393354] page:c00c0000007d1b40 refcount:3 mapcount:0 mapping:c0000001fc03e950 index:0xe7b
[ 9784.393355] def_blk_aops
[ 9784.393356] flags: 0x3ffff800002062(referenced|active|workingset|private)
[ 9784.393358] raw: 003ffff800002062 c0000001b9343a68 c0000001b9343a68 c0000001fc03e950
[ 9784.393359] raw: 0000000000000e7b c000000006607b18 00000003ffffffff c00000000490d000
[ 9784.393359] page dumped because: migration failure
[ 9784.393360] page->mem_cgroup:c00000000490d000
[ 9784.393416] migrating pfn 1f46d failed ret:1
...
$ grep "page dumped because: migration failure" /var/log/kern.log | wc -l
2405558
$ ls -la /var/log/kern.log
-rw-r----- 1 syslog adm 2256109539 Jun 30 14:19 /var/log/kern.log
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
The import was working around the fact "tuple[T]" was used instead of
typing.Tuple[T].
Convert it to use type.Tuple to be consistent with how the rest of the
code is anotated.
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Tested-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
We have a few ref counters srv_count, ses_count and
tc_count which we use for ref counting. Added a WARN_ON
during the decrement of each of these counters to make
sure that they don't go below their minimum values.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull devicetree fixes from Rob Herring:
- Drop 'resets' as required on renesas,du
- Moving of fixed string patterns for 'properties' instead of
'patternProperties'
- Drop more redundant minItems/maxItems that we merged in the merge
window
- Indentation warning fix for sja1105
* tag 'devicetree-fixes-for-5.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
dt-bindings: display: renesas,du: Make resets optional on R-Car H1
dt-bindings: Move fixed string 'patternProperties' to 'properties'
dt-bindings: More dropping redundant minItems/maxItems
dt-bindings: net: dsa: sja1105: Fix indentation warnings
The histogram logic was allowing events with char * pointers to be used as
normal strings. But it was easy to crash the kernel with:
# echo 'hist:keys=filename' > events/syscalls/sys_enter_openat/trigger
And open some files, and boom!
BUG: unable to handle page fault for address: 00007f2ced0c3280
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 1173fa067 P4D 1173fa067 PUD 1171b6067 PMD 1171dd067 PTE 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 6 PID: 1810 Comm: cat Not tainted 5.13.0-rc5-test+ #61
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01
v03.03 07/14/2016
RIP: 0010:strlen+0x0/0x20
Code: f6 82 80 2a 0b a9 20 74 11 0f b6 50 01 48 83 c0 01 f6 82 80 2a 0b
a9 20 75 ef c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <80> 3f 00 74
10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3
RSP: 0018:ffffbdbf81567b50 EFLAGS: 00010246
RAX: 0000000000000003 RBX: ffff93815cdb3800 RCX: ffff9382401a22d0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 00007f2ced0c3280
RBP: 0000000000000100 R08: ffff9382409ff074 R09: ffffbdbf81567c98
R10: ffff9382409ff074 R11: 0000000000000000 R12: ffff9382409ff074
R13: 0000000000000001 R14: ffff93815a744f00 R15: 00007f2ced0c3280
FS: 00007f2ced0f8580(0000) GS:ffff93825a800000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2ced0c3280 CR3: 0000000107069005 CR4: 00000000001706e0
Call Trace:
event_hist_trigger+0x463/0x5f0
? find_held_lock+0x32/0x90
? sched_clock_cpu+0xe/0xd0
? lock_release+0x155/0x440
? kernel_init_free_pages+0x6d/0x90
? preempt_count_sub+0x9b/0xd0
? kernel_init_free_pages+0x6d/0x90
? get_page_from_freelist+0x12c4/0x1680
? __rb_reserve_next+0xe5/0x460
? ring_buffer_lock_reserve+0x12a/0x3f0
event_triggers_call+0x52/0xe0
ftrace_syscall_enter+0x264/0x2c0
syscall_trace_enter.constprop.0+0x1ee/0x210
do_syscall_64+0x1c/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Where it triggered a fault on strlen(key) where key was the filename.
The reason is that filename is a char * to user space, and the histogram
code just blindly dereferenced it, with obvious bad results.
I originally tried to use strncpy_from_user/kernel_nofault() but found
that there's other places that its dereferenced and not worth the effort.
Just do not allow "char *" to act like strings.
Link: https://lkml.kernel.org/r/20210715000206.025df9d2@rorschach.local.home
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: stable@vger.kernel.org
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Tom Zanussi <zanussi@kernel.org>
Fixes: 79e577cbce4c4 ("tracing: Support string type key properly")
Fixes: 5967bd5c4239 ("tracing: Let filter_assign_type() detect FILTER_PTR_STRING")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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