linux.git/kernel/trace/blktrace.c, branch v6.12.80

blktrace: convert strncpy() to strscpy_pad()

2024-04-26T04:07:08+00:00

gcc-9 warns about a possibly non-terminated string copy:

kernel/trace/blktrace.c: In function 'do_blk_trace_setup':
kernel/trace/blktrace.c:527:2: error: 'strncpy' specified bound 32 equals destination size [-Werror=stringop-truncation]

Newer versions are fine here because they see the following explicit
nul-termination. Using strscpy_pad() avoids the warning and
simplifies the code a little. The padding helps  give a clean
buffer to userspace.

Link: https://lkml.kernel.org/r/20240409140059.3806717-5-arnd@kernel.org
Signed-off-by: Arnd Bergmann 
Acked-by: Justin Stitt 
Cc: Alexey Starikovskiy 
Cc: Bob Moore 
Cc: Jens Axboe 
Cc: Len Brown 
Cc: Lin Ming 
Cc: Masahiro Yamada 
Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Cc: Nathan Chancellor 
Cc: Nicolas Schier 
Cc: Rafael J. Wysocki 
Cc: "Richard Russon (FlatCap)" 
Cc: Steven Rostedt 
Signed-off-by: Andrew Morton

block: remove more NULL checks after bdev_get_queue()

2023-02-21T16:23:22+00:00

bdev_get_queue() never returns NULL. Several commits [1][2] have been made
before to remove such superfluous checks, but some still remained.

For places where bdev_get_queue() is called solely for NULL checks, it is
removed entirely.

[1] commit ec9fd2a13d74 ("blk-lib: don't check bdev_get_queue() NULL check")
[2] commit fea127b36c93 ("block: remove superfluous check for request queue in bdev_is_zoned()")

Signed-off-by: Juhyung Park 
Reviewed-by: Pankaj Raghav 
Link: https://lore.kernel.org/r/20230203024029.48260-1-qkrwngud825@gmail.com
Signed-off-by: Jens Axboe

trace/blktrace: fix memory leak with using debugfs_lookup()

2023-02-06T16:29:30+00:00

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Cc: Jens Axboe 
Cc: Steven Rostedt 
Cc: Masami Hiramatsu 
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman 
Reviewed-by: Bart Van Assche 
Link: https://lore.kernel.org/r/20230202141956.2299521-1-gregkh@linuxfoundation.org
Signed-off-by: Jens Axboe

blktrace: Fix output non-blktrace event when blk_classic option enabled

2022-12-08T16:26:11+00:00

When the blk_classic option is enabled, non-blktrace events must be
filtered out. Otherwise, events of other types are output in the blktrace
classic format, which is unexpected.

The problem can be triggered in the following ways:

  # echo 1 > /sys/kernel/debug/tracing/options/blk_classic
  # echo 1 > /sys/kernel/debug/tracing/events/enable
  # echo blk > /sys/kernel/debug/tracing/current_tracer
  # cat /sys/kernel/debug/tracing/trace_pipe

Fixes: c71a89615411 ("blktrace: add ftrace plugin")
Signed-off-by: Yang Jihong 
Link: https://lore.kernel.org/r/20221122040410.85113-1-yangjihong1@huawei.com
Signed-off-by: Jens Axboe

block: bdev & blktrace: use consistent function doc. notation

2022-12-01T16:16:46+00:00

Use only one hyphen in kernel-doc notation between the function name
and its short description.

The is the documented kerenl-doc format. It also fixes the HTML
presentation to be consistent with other functions.

Signed-off-by: Randy Dunlap 
Cc: Jens Axboe 
Cc: linux-block@vger.kernel.org
Link: https://lore.kernel.org/r/20221201070331.25685-1-rdunlap@infradead.org
Signed-off-by: Jens Axboe

blktrace: remove unnessary stop block trace in 'blk_trace_shutdown'

2022-10-20T13:02:52+00:00

As previous commit, 'blk_trace_cleanup' will stop block trace if
block trace's state is 'Blktrace_running'.
So remove unnessary stop block trace in 'blk_trace_shutdown'.

Signed-off-by: Ye Bin 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20221019033602.752383-4-yebin@huaweicloud.com
Signed-off-by: Jens Axboe

blktrace: fix possible memleak in '__blk_trace_remove'

2022-10-20T13:02:52+00:00

When test as follows:
step1: ioctl(sda, BLKTRACESETUP, &arg)
step2: ioctl(sda, BLKTRACESTART, NULL)
step3: ioctl(sda, BLKTRACETEARDOWN, NULL)
step4: ioctl(sda, BLKTRACESETUP, &arg)
Got issue as follows:
debugfs: File 'dropped' in directory 'sda' already present!
debugfs: File 'msg' in directory 'sda' already present!
debugfs: File 'trace0' in directory 'sda' already present!

And also find syzkaller report issue like "KASAN: use-after-free Read in relay_switch_subbuf"
"https://syzkaller.appspot.com/bug?id=13849f0d9b1b818b087341691be6cc3ac6a6bfb7"

If remove block trace without stop(BLKTRACESTOP) block trace, '__blk_trace_remove'
will just set 'q->blk_trace' with NULL. However, debugfs file isn't removed, so
will report file already present when call BLKTRACESETUP.
static int __blk_trace_remove(struct request_queue *q)
{
        struct blk_trace *bt;

        bt = rcu_replace_pointer(q->blk_trace, NULL,
                                 lockdep_is_held(&q->debugfs_mutex));
        if (!bt)
                return -EINVAL;

	if (bt->trace_state != Blktrace_running)
        	blk_trace_cleanup(q, bt);

        return 0;
}

If do test as follows:
step1: ioctl(sda, BLKTRACESETUP, &arg)
step2: ioctl(sda, BLKTRACESTART, NULL)
step3: ioctl(sda, BLKTRACETEARDOWN, NULL)
step4: remove sda

There will remove debugfs directory which will remove recursively all file
under directory.
>> blk_release_queue
>>	debugfs_remove_recursive(q->debugfs_dir)
So all files which created in 'do_blk_trace_setup' are removed, and
'dentry->d_inode' is NULL. But 'q->blk_trace' is still in 'running_trace_lock',
'trace_note_tsk' will traverse 'running_trace_lock' all nodes.
>>trace_note_tsk
>>  trace_note
>>    relay_reserve
>>       relay_switch_subbuf
>>        d_inode(buf->dentry)->i_size

To solve above issues, reference commit '5afedf670caf', call 'blk_trace_cleanup'
unconditionally in '__blk_trace_remove' and first stop block trace in
'blk_trace_cleanup'.

Signed-off-by: Ye Bin 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20221019033602.752383-3-yebin@huaweicloud.com
Signed-off-by: Jens Axboe

blktrace: introduce 'blk_trace_{start,stop}' helper

2022-10-20T13:02:52+00:00

Introduce 'blk_trace_{start,stop}' helper. No functional changed.

Signed-off-by: Ye Bin 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20221019033602.752383-2-yebin@huaweicloud.com
Signed-off-by: Jens Axboe

blktrace: Fix the blk_fill_rwbs() kernel-doc header

2022-07-15T19:10:04+00:00

Reflect recent changes in the blk_fill_rwbs() kernel-doc header.

Reported-by: Stephen Rothwell 
Cc: Christoph Hellwig 
Cc: Steven Rostedt 
Cc: Li Zefan 
Cc: Chaitanya Kulkarni 
Cc: Stephen Rothwell 
Fixes: 919dbca8670d ("blktrace: Use the new blk_opf_t type")
Signed-off-by: Bart Van Assche 
Link: https://lore.kernel.org/r/20220715184735.2326034-3-bvanassche@acm.org
Signed-off-by: Jens Axboe

blktrace: Use the new blk_opf_t type

2022-07-14T18:14:30+00:00

Improve static type checking by using the new blk_opf_t type for a function
argument that represents a combination of a request operation and request
flags. Rename that argument from 'op' into 'opf' to make its role more
clear.

Cc: Christoph Hellwig 
Cc: Steven Rostedt 
Cc: Li Zefan 
Cc: Chaitanya Kulkarni 
Signed-off-by: Bart Van Assche 
Link: https://lore.kernel.org/r/20220714180729.1065367-12-bvanassche@acm.org
Signed-off-by: Jens Axboe