linux-toradex.git/lib/test_lockup.c, branch v5.12-rc5

lib/test_lockup.c: minimum fix to get it compiled on PREEMPT_RT

2020-12-16T06:46:16+00:00

On PREEMPT_RT the locks are quite different so they can't be tested as it
is done below.  The alternative is to test for the waitlock within
rtmutex.

This is the bare minimun to get it compiled.  Problems which exist on
PREEMP_RT:

 - none of the locks (spinlock_t, rwlock_t, mutex_t, rw_semaphore) may
   be acquired with disabled preemption or interrupts.

   If I read the code correct the it is possible to acquire a mutex_t
   with disabled interrupts.

   I don't know how to obtain a lock pointer. Technically they are not
   exported to userland.

 - memory can not be allocated with disabled preemption or interrupts
   even with GFP_ATOMIC.

Link: https://lkml.kernel.org/r/20201028181041.xyeothhkouc3p4md@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior 
Cc: Konstantin Khlebnikov 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/test_lockup.c: fix return value of test_lockup_init()

2020-08-12T17:58:00+00:00

Since filp_open() returns an error pointer, we should use IS_ERR() to
check the return value and then return PTR_ERR() if failed to get the
actual return value instead of always -EINVAL.

E.g. without this patch:

[root@localhost loongson]# ls no_such_file
ls: cannot access no_such_file: No such file or directory
[root@localhost loongson]# modprobe test_lockup file_path=no_such_file lock_sb_umount time_secs=60 state=S
modprobe: ERROR: could not insert 'test_lockup': Invalid argument
[root@localhost loongson]# dmesg | tail -1
[  126.100596] test_lockup: cannot find file_path

With this patch:

[root@localhost loongson]# ls no_such_file
ls: cannot access no_such_file: No such file or directory
[root@localhost loongson]# modprobe test_lockup file_path=no_such_file lock_sb_umount time_secs=60 state=S
modprobe: ERROR: could not insert 'test_lockup': Unknown symbol in module, or unknown parameter (see dmesg)
[root@localhost loongson]# dmesg | tail -1
[   95.134362] test_lockup: failed to open no_such_file: -2

Fixes: aecd42df6d39 ("lib/test_lockup.c: add parameters for locking generic vfs locks")
Signed-off-by: Tiezhu Yang 
Signed-off-by: Andrew Morton 
Reviewed-by: Guenter Roeck 
Cc: Konstantin Khlebnikov 
Cc: Kees Cook 
Link: http://lkml.kernel.org/r/1595555407-29875-2-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Linus Torvalds

lib/test_lockup.c: make symbol 'test_works' static

2020-08-12T17:57:59+00:00

Fix sparse build warning:

lib/test_lockup.c:403:1: warning:
 symbol '__pcpu_scope_test_works' was not declared. Should it be static?

Reported-by: Hulk Robot 
Signed-off-by: Wei Yongjun 
Signed-off-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200707112252.9047-1-weiyongjun1@huawei.com
Signed-off-by: Linus Torvalds

treewide: Remove uninitialized_var() usage

2020-07-16T19:35:15+00:00

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky  # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe  # IB
Acked-by: Kalle Valo  # wireless drivers
Reviewed-by: Chao Yu  # erofs
Signed-off-by: Kees Cook

maccess: rename probe_kernel_address to get_kernel_nofault

2020-06-18T18:14:40+00:00

Better describe what this helper does, and match the naming of
copy_from_kernel_nofault.

Also switch the argument order around, so that it acts and looks
like get_user().

Signed-off-by: Christoph Hellwig 
Signed-off-by: Linus Torvalds

mmap locking API: convert mmap_sem comments

2020-06-09T16:39:14+00:00

Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]

Signed-off-by: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Daniel Jordan 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Laurent Dufour 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds

mmap locking API: use coccinelle to convert mmap_sem rwsem call sites

2020-06-09T16:39:14+00:00

This change converts the existing mmap_sem rwsem calls to use the new mmap
locking API instead.

The change is generated using coccinelle with the following rule:

// spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir .

@@
expression mm;
@@
(
-init_rwsem
+mmap_init_lock
|
-down_write
+mmap_write_lock
|
-down_write_killable
+mmap_write_lock_killable
|
-down_write_trylock
+mmap_write_trylock
|
-up_write
+mmap_write_unlock
|
-downgrade_write
+mmap_write_downgrade
|
-down_read
+mmap_read_lock
|
-down_read_killable
+mmap_read_lock_killable
|
-down_read_trylock
+mmap_read_trylock
|
-up_read
+mmap_read_unlock
)
-(&mm->mmap_sem)
+(mm)

Signed-off-by: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Reviewed-by: Daniel Jordan 
Reviewed-by: Laurent Dufour 
Reviewed-by: Vlastimil Babka 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com
Signed-off-by: Linus Torvalds

lib/test_lockup.c: make test_inode static

2020-06-05T02:06:25+00:00

Fix the following sparse warning:

  lib/test_lockup.c:145:14: warning: symbol 'test_inode' was not declared.
  Should it be static?

Reported-by: Hulk Robot 
Signed-off-by: Jason Yan 
Signed-off-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200417074021.46411-1-yanaijie@huawei.com
Signed-off-by: Linus Torvalds

lib/test_lockup.c: add parameters for locking generic vfs locks

2020-04-07T17:43:42+00:00

file_path=	defines file or directory to open
lock_inode=Y		set lock_rwsem_ptr to inode->i_rwsem
lock_mapping=Y		set lock_rwsem_ptr to mapping->i_mmap_rwsem
lock_sb_umount=Y	set lock_rwsem_ptr to sb->s_umount

This gives safe and simple way to see how system reacts to contention of
common vfs locks and how syscalls depend on them directly or indirectly.

For example to block s_umount for 60 seconds:
# modprobe test_lockup file_path=. lock_sb_umount time_secs=60 state=S

This is useful for checking/testing scalability issues like this:
https://lore.kernel.org/lkml/158497590858.7371.9311902565121473436.stgit@buzz/

Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Andrew Morton 
Cc: Colin Ian King 
Cc: Greg Kroah-Hartman 
Cc: Guenter Roeck 
Cc: Kees Cook 
Cc: Peter Zijlstra 
Cc: Petr Mladek 
Cc: Sasha Levin 
Cc: Sergey Senozhatsky 
Cc: Steven Rostedt 
Link: http://lkml.kernel.org/r/158498153964.5621.83061779039255681.stgit@buzz
Signed-off-by: Linus Torvalds

lib/test_lockup.c: fix spelling mistake "iteraions" -> "iterations"

2020-04-07T17:43:42+00:00

There is a spelling mistake in a pr_notice message.  Fix it.

Signed-off-by: Colin Ian King 
Signed-off-by: Andrew Morton 
Cc: Greg Kroah-Hartman 
Cc: Guenter Roeck 
Cc: Kees Cook 
Cc: Konstantin Khlebnikov 
Cc: Peter Zijlstra 
Cc: Petr Mladek 
Cc: Sasha Levin 
Cc: Sergey Senozhatsky 
Cc: Steven Rostedt 
Link: http://lkml.kernel.org/r/20200221155145.79522-1-colin.king@canonical.com
Signed-off-by: Linus Torvalds