linux.git/fs/proc/base.c, branch v2.6.29

Avoid 64-bit "switch()" statements on 32-bit architectures

2009-03-17T17:02:35+00:00

Commit ee6f779b9e0851e2f7da292a9f58e0095edf615a ("filp->f_pos not
correctly updated in proc_task_readdir") changed the proc code to use
filp->f_pos directly, rather than through a temporary variable.  In the
process, that caused the operations to be done on the full 64 bits, even
though the offset is never that big.

That's all fine and dandy per se, but for some unfathomable reason gcc
generates absolutely horrid code when using 64-bit values in switch()
statements.  To the point of actually calling out to gcc helper
functions like __cmpdi2 rather than just doing the trivial comparisons
directly the way gcc does for normal compares.  At which point we get
link failures, because we really don't want to support that kind of
crazy code.

Fix this by just casting the f_pos value to "unsigned long", which
is plenty big enough for /proc, and avoids the gcc code generation issue.

Reported-by: Alexey Dobriyan 
Cc: Zhang Le 
Signed-off-by: Linus Torvalds

filp->f_pos not correctly updated in proc_task_readdir

2009-03-16T14:51:33+00:00

filp->f_pos only get updated at the end of the function. Thus d_off of those
dirents who are in the middle will be 0, and this will cause a problem in
glibc's readdir implementation, specifically endless loop. Because when overflow
occurs, f_pos will be set to next dirent to read, however it will be 0, unless
the next one is the last one. So it will start over again and again.

There is a sample program in man 2 gendents. This is the output of the program
running on a multithread program's task dir before this patch is applied:

  $ ./a.out /proc/3807/task
  --------------- nread=128 ---------------
  i-node#  file type  d_reclen  d_off   d_name
    506442  directory    16          1  .
    506441  directory    16          0  ..
    506443  directory    16          0  3807
    506444  directory    16          0  3809
    506445  directory    16          0  3812
    506446  directory    16          0  3861
    506447  directory    16          0  3862
    506448  directory    16          8  3863

This is the output after this patch is applied

  $ ./a.out /proc/3807/task
  --------------- nread=128 ---------------
  i-node#  file type  d_reclen  d_off   d_name
    506442  directory    16          1  .
    506441  directory    16          2  ..
    506443  directory    16          3  3807
    506444  directory    16          4  3809
    506445  directory    16          5  3812
    506446  directory    16          6  3861
    506447  directory    16          7  3862
    506448  directory    16          8  3863

Signed-off-by: Zhang Le 
Acked-by: Al Viro 
Signed-off-by: Linus Torvalds

Merge branch 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc

2009-01-07T20:01:06+00:00

* 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc:
  proc: remove write-only variable in proc_pident_lookup()
  proc: fix sparse warning
  proc: add /proc/*/stack
  proc: remove '##' usage
  proc: remove useless WARN_ONs
  proc: stop using BKL

zero i_uid/i_gid on inode allocation

2009-01-05T16:54:28+00:00

... and don't bother in callers.  Don't bother with zeroing i_blocks,
while we are at it - it's already been zeroed.

i_mode is not worth the effort; it has no common default value.

Signed-off-by: Al Viro

proc: remove write-only variable in proc_pident_lookup()

2009-01-05T09:27:45+00:00

Signed-off-by: WANG Cong 
Signed-off-by: Alexey Dobriyan

proc: fix sparse warning

2009-01-05T09:27:45+00:00

fs/proc/base.c:312:4: warning: do-while statement is not a compound statement

Signed-off-by: Hannes Eder 
Signed-off-by: Alexey Dobriyan

proc: add /proc/*/stack

2009-01-05T09:27:44+00:00

/proc/*/stack adds the ability to query a task's stack trace. It is more
useful than /proc/*/wchan as it provides full stack trace instead of single
depth. Example output:

	$ cat /proc/self/stack
	[] save_stack_trace_tsk+0x17/0x35
	[] proc_pid_stack+0x4a/0x76
	[] proc_single_show+0x4a/0x5e
	[] seq_read+0xf3/0x29f
	[] vfs_read+0x6d/0x91
	[] sys_read+0x3b/0x60
	[] syscall_call+0x7/0xb
	[] 0xffffffff

[add save_stack_trace_tsk() on mips, ACK Ralf --adobriyan]
Signed-off-by: Ken Chen 
Signed-off-by: Ingo Molnar 
Signed-off-by: Alexey Dobriyan

proc: remove '##' usage

2009-01-05T09:27:44+00:00

Inability to jump to /proc/*/foo handlers with ctags is annoying.

Signed-off-by: Alexey Dobriyan

proc: remove useless WARN_ONs

2009-01-05T09:27:44+00:00

NULL "struct inode *" means VFS passed NULL inode to ->open.

Signed-off-by: Alexey Dobriyan

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2008-12-28T20:27:58+00:00

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (31 commits)
  sched: fix warning in fs/proc/base.c
  schedstat: consolidate per-task cpu runtime stats
  sched: use RCU variant of list traversal in for_each_leaf_rt_rq()
  sched, cpuacct: export percpu cpuacct cgroup stats
  sched, cpuacct: refactoring cpuusage_read / cpuusage_write
  sched: optimize update_curr()
  sched: fix wakeup preemption clock
  sched: add missing arch_update_cpu_topology() call
  sched: let arch_update_cpu_topology indicate if topology changed
  sched: idle_balance() does not call load_balance_newidle()
  sched: fix sd_parent_degenerate on non-numa smp machine
  sched: add uid information to sched_debug for CONFIG_USER_SCHED
  sched: move double_unlock_balance() higher
  sched: update comment for move_task_off_dead_cpu
  sched: fix inconsistency when redistribute per-cpu tg->cfs_rq shares
  sched/rt: removed unneeded defintion
  sched: add hierarchical accounting to cpu accounting controller
  sched: include group statistics in /proc/sched_debug
  sched: rename SCHED_NO_NO_OMIT_FRAME_POINTER => SCHED_OMIT_FRAME_POINTER
  sched: clean up SCHED_CPUMASK_ALLOC
  ...