linux.git/fs/seq_file.c, branch v6.6.131

use less confusing names for iov_iter direction initializers

2022-11-25T18:01:55+00:00

READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro

rxrpc: Fix locking issue

2022-05-22T20:03:01+00:00

There's a locking issue with the per-netns list of calls in rxrpc.  The
pieces of code that add and remove a call from the list use write_lock()
and the calls procfile uses read_lock() to access it.  However, the timer
callback function may trigger a removal by trying to queue a call for
processing and finding that it's already queued - at which point it has a
spare refcount that it has to do something with.  Unfortunately, if it puts
the call and this reduces the refcount to 0, the call will be removed from
the list.  Unfortunately, since the _bh variants of the locking functions
aren't used, this can deadlock.

================================
WARNING: inconsistent lock state
5.18.0-rc3-build4+ #10 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
ksoftirqd/2/25 [HC0[0]:SC1[1]:HE1:SE0] takes:
ffff888107ac4038 (&rxnet->call_lock){+.?.}-{2:2}, at: rxrpc_put_call+0x103/0x14b
{SOFTIRQ-ON-W} state was registered at:
...
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&rxnet->call_lock);
  
    lock(&rxnet->call_lock);

 *** DEADLOCK ***

1 lock held by ksoftirqd/2/25:
 #0: ffff8881008ffdb0 ((&call->timer)){+.-.}-{0:0}, at: call_timer_fn+0x5/0x23d

Changes
=======
ver #2)
 - Changed to using list_next_rcu() rather than rcu_dereference() directly.

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org
Signed-off-by: David S. Miller

seq_file: fix NULL pointer arithmetic warning

2022-02-01T16:31:55+00:00

Implement conditional logic in order to replace NULL pointer arithmetic.

The use of NULL pointer arithmetic was pointed out by clang with the
following warning:

fs/kernfs/file.c:128:15: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
                return NULL + !*ppos;
                       ~~~~ ^
fs/seq_file.c:559:14: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
        return NULL + (*pos == 0);

Signed-off-by: Maíra Canal 
Signed-off-by: Al Viro

seq_file: move seq_escape() to a header

2021-11-09T18:02:52+00:00

Move seq_escape() to the header as inliner, for a small kernel text size
reduction.

Link: https://lkml.kernel.org/r/20211001122917.67228-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

seq_file: disallow extremely large seq buffer allocations

2021-07-20T00:18:48+00:00

There is no reasonable need for a buffer larger than this, and it avoids
int overflow pitfalls.

Fixes: 058504edd026 ("fs/seq_file: fallback to vmalloc allocation")
Suggested-by: Al Viro 
Reported-by: Qualys Security Advisory 
Signed-off-by: Eric Sandeen 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds

seq_file: drop unused *_escape_mem_ascii()

2021-07-01T18:06:05+00:00

There are no more users of the seq_escape_mem_ascii() followed by
string_escape_mem_ascii().

Remove them for good.

Link: https://lkml.kernel.org/r/20210504180819.73127-16-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Cc: Alexander Viro 
Cc: Chuck Lever 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

seq_file: convert seq_escape() to use seq_escape_str()

2021-07-01T18:06:05+00:00

Convert seq_escape() to use seq_escape_str() rather than open coding it.

Note, for now we leave it as an exported symbol due to some old code that
can't tolerate ctype.h being (indirectly) included.

Link: https://lkml.kernel.org/r/20210504180819.73127-14-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Cc: Alexander Viro 
Cc: Chuck Lever 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

seq_file: introduce seq_escape_mem()

2021-07-01T18:06:05+00:00

Introduce seq_escape_mem() to allow users to pass additional parameters to
string_escape_mem().

Link: https://lkml.kernel.org/r/20210504180819.73127-12-andriy.shevchenko@linux.intel.com
Suggested-by: Al Viro 
Signed-off-by: Andy Shevchenko 
Cc: Chuck Lever 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

seq_file: Add a seq_bprintf function

2021-04-27T22:50:15+00:00

Similarly to seq_buf_bprintf in lib/seq_buf.c, this function writes a
printf formatted string with arguments provided in a "binary
representation" built by functions such as vbin_printf.

Signed-off-by: Florent Revest 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210427174313.860948-2-revest@chromium.org

fs: fix kernel-doc markups

2021-01-21T21:06:00+00:00

Two markups are at the wrong place. Kernel-doc only
support having the comment just before the identifier.

Also, some identifiers have different names between their
prototypes and the kernel-doc markup.

Signed-off-by: Mauro Carvalho Chehab 
Link: https://lore.kernel.org/r/96b1e1b388600ab092331f6c4e88ff8e8779ce6c.1610610937.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet