* [patch, validator] fix proc_subdir_lock related deadlock
@ 2006-01-25 17:03 Ingo Molnar
2006-01-25 17:14 ` Steven Rostedt
0 siblings, 1 reply; 8+ messages in thread
From: Ingo Molnar @ 2006-01-25 17:03 UTC (permalink / raw)
To: Andrew Morton; +Cc: Steven Rostedt, linux-kernel
proc_subdir_lock can also be used from softirq (tasklet) context, which
may lead to deadlocks.
This bug was found via the lock validator:
============================
[ BUG: illegal lock usage! ]
----------------------------
illegal {enabled-softirqs} -> {used-in-softirq} usage.
ifup/2283 [HC0[0]:SC1[2]:HE1:SE0] takes {proc_subdir_lock [u:25]}, at:
[<c0196363>] remove_proc_entry+0x33/0x1f0
{enabled-softirqs} state was registered at:
[<c04d7c0d>] _spin_unlock_bh+0xd/0x10
hardirqs last enabled at: [<c04d7bb5>] _spin_unlock_irqrestore+0x25/0x30
softirqs last enabled at: [<c0127624>] free_uid+0x24/0x80
other info that might help in debugging this:
------------------------------
| showing all locks held by: | (ifup/2283 [c31a6790, 125]):
------------------------------
[<c010432d>] show_trace+0xd/0x10
[<c0104347>] dump_stack+0x17/0x20
[<c0137181>] print_usage_bug+0x1e1/0x200
[<c0137739>] mark_lock+0x259/0x290
[<c0137bd5>] debug_lock_chain_spin+0x465/0x10f0
[<c0264a6d>] _raw_spin_lock+0x2d/0x90
[<c04d7a18>] _spin_lock+0x8/0x10
[<c0196363>] remove_proc_entry+0x33/0x1f0
[<c0141d79>] unregister_handler_proc+0x19/0x20
[<c014153b>] free_irq+0x7b/0xe0
[<c02f15e2>] floppy_release_irq_and_dma+0x1b2/0x210
[<c02efad7>] set_dor+0xc7/0x1b0
[<c02f2b51>] motor_off_callback+0x21/0x30
[<c01272b5>] run_timer_softirq+0xf5/0x1f0
[<c0122c17>] __do_softirq+0x87/0x120
[<c0105519>] do_softirq+0x69/0xb0
=======================
the way i fixed this bug was to make all uses of the proc_subdir_lock
softirq-safe. Alternatively, we may want to forbid the use of this lock
(and remove_proc_entry()) from softirq contexts - but a quick glance
showed that quite some drivers are affected, and it would need a full
review to make sure the block is never taken from a softirq context. So
this seemed the safest fix.
the patched 2.6.16-rc1-mm1 kernel now passes validation.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
----
fs/proc/generic.c | 34 +++++++++++++++++++---------------
fs/proc/proc_devtree.c | 4 ++--
2 files changed, 21 insertions(+), 17 deletions(-)
Index: linux/fs/proc/generic.c
===================================================================
--- linux.orig/fs/proc/generic.c
+++ linux/fs/proc/generic.c
@@ -30,6 +30,10 @@ static ssize_t proc_file_write(struct fi
size_t count, loff_t *ppos);
static loff_t proc_file_lseek(struct file *, loff_t, int);
+/*
+ * Is mostly used from process, but can occasionally be used from
+ * softirq context too - hence all locking must be softirq-safe:
+ */
DEFINE_SPINLOCK(proc_subdir_lock);
int proc_match(int len, const char *name, struct proc_dir_entry *de)
@@ -282,7 +286,7 @@ static int xlate_proc_name(const char *n
int len;
int rtn = 0;
- spin_lock(&proc_subdir_lock);
+ spin_lock_bh(&proc_subdir_lock);
de = &proc_root;
while (1) {
next = strchr(cp, '/');
@@ -303,7 +307,7 @@ static int xlate_proc_name(const char *n
*residual = cp;
*ret = de;
out:
- spin_unlock(&proc_subdir_lock);
+ spin_unlock_bh(&proc_subdir_lock);
return rtn;
}
@@ -389,7 +393,7 @@ struct dentry *proc_lookup(struct inode
int error = -ENOENT;
lock_kernel();
- spin_lock(&proc_subdir_lock);
+ spin_lock_bh(&proc_subdir_lock);
de = PDE(dir);
if (de) {
for (de = de->subdir; de ; de = de->next) {
@@ -398,15 +402,15 @@ struct dentry *proc_lookup(struct inode
if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
unsigned int ino = de->low_ino;
- spin_unlock(&proc_subdir_lock);
+ spin_unlock_bh(&proc_subdir_lock);
error = -EINVAL;
inode = proc_get_inode(dir->i_sb, ino, de);
- spin_lock(&proc_subdir_lock);
+ spin_lock_bh(&proc_subdir_lock);
break;
}
}
}
- spin_unlock(&proc_subdir_lock);
+ spin_unlock_bh(&proc_subdir_lock);
unlock_kernel();
if (inode) {
@@ -460,13 +464,13 @@ int proc_readdir(struct file * filp,
filp->f_pos++;
/* fall through */
default:
- spin_lock(&proc_subdir_lock);
+ spin_lock_bh(&proc_subdir_lock);
de = de->subdir;
i -= 2;
for (;;) {
if (!de) {
ret = 1;
- spin_unlock(&proc_subdir_lock);
+ spin_unlock_bh(&proc_subdir_lock);
goto out;
}
if (!i)
@@ -477,15 +481,15 @@ int proc_readdir(struct file * filp,
do {
/* filldir passes info to user space */
- spin_unlock(&proc_subdir_lock);
+ spin_unlock_bh(&proc_subdir_lock);
if (filldir(dirent, de->name, de->namelen, filp->f_pos,
de->low_ino, de->mode >> 12) < 0)
goto out;
- spin_lock(&proc_subdir_lock);
+ spin_lock_bh(&proc_subdir_lock);
filp->f_pos++;
de = de->next;
} while (de);
- spin_unlock(&proc_subdir_lock);
+ spin_unlock_bh(&proc_subdir_lock);
}
ret = 1;
out: unlock_kernel();
@@ -520,11 +524,11 @@ static int proc_register(struct proc_dir
return -EAGAIN;
dp->low_ino = i;
- spin_lock(&proc_subdir_lock);
+ spin_lock_bh(&proc_subdir_lock);
dp->next = dir->subdir;
dp->parent = dir;
dir->subdir = dp;
- spin_unlock(&proc_subdir_lock);
+ spin_unlock_bh(&proc_subdir_lock);
if (S_ISDIR(dp->mode)) {
if (dp->proc_iops == NULL) {
@@ -718,7 +722,7 @@ void remove_proc_entry(const char *name,
goto out;
len = strlen(fn);
- spin_lock(&proc_subdir_lock);
+ spin_lock_bh(&proc_subdir_lock);
for (p = &parent->subdir; *p; p=&(*p)->next ) {
if (!proc_match(len, fn, *p))
continue;
@@ -739,7 +743,7 @@ void remove_proc_entry(const char *name,
}
break;
}
- spin_unlock(&proc_subdir_lock);
+ spin_unlock_bh(&proc_subdir_lock);
out:
return;
}
Index: linux/fs/proc/proc_devtree.c
===================================================================
--- linux.orig/fs/proc/proc_devtree.c
+++ linux/fs/proc/proc_devtree.c
@@ -136,11 +136,11 @@ void proc_device_tree_add_node(struct de
* properties are quite unimportant for us though, thus we
* simply "skip" them here, but we do have to check.
*/
- spin_lock(&proc_subdir_lock);
+ spin_lock_bh(&proc_subdir_lock);
for (ent = de->subdir; ent != NULL; ent = ent->next)
if (!strcmp(ent->name, pp->name))
break;
- spin_unlock(&proc_subdir_lock);
+ spin_unlock_bh(&proc_subdir_lock);
if (ent != NULL) {
printk(KERN_WARNING "device-tree: property \"%s\" name"
" conflicts with node in %s\n", pp->name,
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [patch, validator] fix proc_subdir_lock related deadlock
2006-01-25 17:03 [patch, validator] fix proc_subdir_lock related deadlock Ingo Molnar
@ 2006-01-25 17:14 ` Steven Rostedt
2006-01-25 18:08 ` Ingo Molnar
0 siblings, 1 reply; 8+ messages in thread
From: Steven Rostedt @ 2006-01-25 17:14 UTC (permalink / raw)
To: Ingo Molnar; +Cc: Andrew Morton, linux-kernel
On Wed, 2006-01-25 at 18:03 +0100, Ingo Molnar wrote:
> proc_subdir_lock can also be used from softirq (tasklet) context, which
> may lead to deadlocks.
>
> This bug was found via the lock validator:
>
Thanks Ingo,
I stressed in sending the patch that there was a big assumption that the
calls would not be done in (soft)irq context. I just didn't want to add
overhead if it wasn't needed. But I guess that this is needed until we
can remove all the instances that use it in softirq context. But that's
for a later patch.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
-- Steve
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [patch, validator] fix proc_subdir_lock related deadlock
2006-01-25 17:14 ` Steven Rostedt
@ 2006-01-25 18:08 ` Ingo Molnar
2006-01-25 18:14 ` [patch, validator] fix files_lock " Ingo Molnar
2006-01-25 18:23 ` [patch, validator] fix proc_subdir_lock " Andrew Morton
0 siblings, 2 replies; 8+ messages in thread
From: Ingo Molnar @ 2006-01-25 18:08 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Andrew Morton, linux-kernel, Alexander Viro
* Steven Rostedt <rostedt@goodmis.org> wrote:
> > proc_subdir_lock can also be used from softirq (tasklet) context, which
> > may lead to deadlocks.
> >
> > This bug was found via the lock validator:
> >
>
> Thanks Ingo,
>
> I stressed in sending the patch that there was a big assumption that
> the calls would not be done in (soft)irq context. I just didn't want
> to add overhead if it wasn't needed. But I guess that this is needed
> until we can remove all the instances that use it in softirq context.
> But that's for a later patch.
the validator just found another problem with this lock, pointing out
that files_lock nests inside of proc_subdir_lock, and that files_lock is
a softirq-unsafe lock, creating another (unlikely but possible) deadlock
scenario:
=====================================
[ BUG: lock inversion bug detected! ]
-------------------------------------
grep/2290 just changed the state of lock {proc_subdir_lock} at:
[<c0196e53>] remove_proc_entry+0x33/0x1f0
but this lock took lock {files_lock} in the past,
acquired at: [<c0196ece>] remove_proc_entry+0xae/0x1f0
and interrupts could create an inverse lock dependency between them,
which could lead to deadlocks!
other info that might help in debugging this:
------------------------------
| showing all locks held by: | (grep/2290 [c321c790, 125]):
------------------------------
[<c010432d>] show_trace+0xd/0x10
[<c0104347>] dump_stack+0x17/0x20
[<c0137b11>] check_no_lock_2_mask+0x131/0x180
[<c0137ffb>] mark_lock+0xfb/0x2a0
[<c01387b3>] debug_lock_chain+0x613/0x10d0
[<c01392ad>] debug_lock_chain_spin+0x3d/0x60
[<c02656ed>] _raw_spin_lock+0x2d/0x90
[<c04d88d2>] _spin_lock_bh+0x12/0x20
[<c0196e53>] remove_proc_entry+0x33/0x1f0
[<c01427c9>] unregister_handler_proc+0x19/0x20
[<c0141f8b>] free_irq+0x7b/0xe0
[<c02f2302>] floppy_release_irq_and_dma+0x1b2/0x210
[<c02f07f7>] set_dor+0xc7/0x1b0
[<c02f3871>] motor_off_callback+0x21/0x30
[<c01273a5>] run_timer_softirq+0xf5/0x1f0
[<c0122cf7>] __do_softirq+0x97/0x130
[<c0105519>] do_softirq+0x69/0x100
=======================
[<c01229a9>] irq_exit+0x39/0x50
[<c010f4cc>] smp_apic_timer_interrupt+0x4c/0x50
[<c010393b>] apic_timer_interrupt+0x27/0x2c
to solve this we must either change files_lock to be softirq-safe too
(bleh!), or we must forbid remove_proc_entry() use from softirq
contexts. Neither is a happy solution - remove_proc_entry() is used
within free_irq(), and who knows how many drivers do free_irq() in
softirq/tasklet context ...
Andrew, this needs to be resolved before v2.6.16, correct? Steve's patch
solves a real bug in the upstream kernel.
Ingo
^ permalink raw reply [flat|nested] 8+ messages in thread
* [patch, validator] fix files_lock related deadlock
2006-01-25 18:08 ` Ingo Molnar
@ 2006-01-25 18:14 ` Ingo Molnar
2006-01-25 18:23 ` [patch, validator] fix proc_subdir_lock " Andrew Morton
1 sibling, 0 replies; 8+ messages in thread
From: Ingo Molnar @ 2006-01-25 18:14 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Andrew Morton, linux-kernel, Alexander Viro
> to solve this we must either change files_lock to be softirq-safe too
> (bleh!), or we must forbid remove_proc_entry() use from softirq
> contexts. Neither is a happy solution - remove_proc_entry() is used
> within free_irq(), and who knows how many drivers do free_irq() in
> softirq/tasklet context ...
>
> Andrew, this needs to be resolved before v2.6.16, correct? Steve's
> patch solves a real bug in the upstream kernel.
the patch below does the easier and safer change: it makes files_lock
softirq-safe. (A quick test shows that the validator does not complain
when this patch is applied too - so it seems the 'softirq effect' does
not spread to other VFS locks.)
Ingo
-----
the validator just found another problem with this lock, pointing out
that files_lock nests inside of proc_subdir_lock, and that files_lock is
a softirq-unsafe lock, creating another (unlikely but possible) deadlock
scenario:
=====================================
[ BUG: lock inversion bug detected! ]
-------------------------------------
grep/2290 just changed the state of lock {proc_subdir_lock} at:
[<c0196e53>] remove_proc_entry+0x33/0x1f0
but this lock took lock {files_lock} in the past,
acquired at: [<c0196ece>] remove_proc_entry+0xae/0x1f0
and interrupts could create an inverse lock dependency between them,
which could lead to deadlocks!
other info that might help in debugging this:
------------------------------
| showing all locks held by: | (grep/2290 [c321c790, 125]):
------------------------------
[<c010432d>] show_trace+0xd/0x10
[<c0104347>] dump_stack+0x17/0x20
[<c0137b11>] check_no_lock_2_mask+0x131/0x180
[<c0137ffb>] mark_lock+0xfb/0x2a0
[<c01387b3>] debug_lock_chain+0x613/0x10d0
[<c01392ad>] debug_lock_chain_spin+0x3d/0x60
[<c02656ed>] _raw_spin_lock+0x2d/0x90
[<c04d88d2>] _spin_lock_bh+0x12/0x20
[<c0196e53>] remove_proc_entry+0x33/0x1f0
[<c01427c9>] unregister_handler_proc+0x19/0x20
[<c0141f8b>] free_irq+0x7b/0xe0
[<c02f2302>] floppy_release_irq_and_dma+0x1b2/0x210
[<c02f07f7>] set_dor+0xc7/0x1b0
[<c02f3871>] motor_off_callback+0x21/0x30
[<c01273a5>] run_timer_softirq+0xf5/0x1f0
[<c0122cf7>] __do_softirq+0x97/0x130
[<c0105519>] do_softirq+0x69/0x100
=======================
[<c01229a9>] irq_exit+0x39/0x50
[<c010f4cc>] smp_apic_timer_interrupt+0x4c/0x50
[<c010393b>] apic_timer_interrupt+0x27/0x2c
to solve this we must either change files_lock to be softirq-safe too
(bleh!), or we must forbid remove_proc_entry() use from softirq
contexts. Neither is a happy solution - remove_proc_entry() is used
within free_irq(), and who knows how many drivers do free_irq() in
softirq/tasklet context ...
the patch below makes files_lock softirq-safe.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
----
include/linux/fs.h | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
Index: linux/include/linux/fs.h
===================================================================
--- linux.orig/include/linux/fs.h
+++ linux/include/linux/fs.h
@@ -648,9 +648,13 @@ struct file {
#endif /* #ifdef CONFIG_EPOLL */
struct address_space *f_mapping;
};
+/*
+ * files_lock can also be taken from softirq context:
+ */
extern spinlock_t files_lock;
-#define file_list_lock() spin_lock(&files_lock);
-#define file_list_unlock() spin_unlock(&files_lock);
+
+#define file_list_lock() spin_lock_bh(&files_lock);
+#define file_list_unlock() spin_unlock_bh(&files_lock);
#define get_file(x) atomic_inc(&(x)->f_count)
#define file_count(x) atomic_read(&(x)->f_count)
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [patch, validator] fix proc_subdir_lock related deadlock
2006-01-25 18:08 ` Ingo Molnar
2006-01-25 18:14 ` [patch, validator] fix files_lock " Ingo Molnar
@ 2006-01-25 18:23 ` Andrew Morton
2006-01-25 20:21 ` Ingo Molnar
2006-01-26 0:02 ` [patch, lock validator] fix proc_inum_lock " Ingo Molnar
1 sibling, 2 replies; 8+ messages in thread
From: Andrew Morton @ 2006-01-25 18:23 UTC (permalink / raw)
To: Ingo Molnar; +Cc: rostedt, linux-kernel, viro
Ingo Molnar <mingo@elte.hu> wrote:
>
>
> * Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > > proc_subdir_lock can also be used from softirq (tasklet) context, which
> > > may lead to deadlocks.
> > >
> > > This bug was found via the lock validator:
> > >
> >
> > Thanks Ingo,
> >
> > I stressed in sending the patch that there was a big assumption that
> > the calls would not be done in (soft)irq context. I just didn't want
> > to add overhead if it wasn't needed. But I guess that this is needed
> > until we can remove all the instances that use it in softirq context.
> > But that's for a later patch.
>
> the validator just found another problem with this lock, pointing out
> that files_lock nests inside of proc_subdir_lock, and that files_lock is
> a softirq-unsafe lock, creating another (unlikely but possible) deadlock
> scenario:
files_lock can be taken on the free_irq() path: proc_kill_inodes().
> ...
> to solve this we must either change files_lock to be softirq-safe too
> (bleh!), or we must forbid remove_proc_entry() use from softirq
> contexts. Neither is a happy solution - remove_proc_entry() is used
> within free_irq(), and who knows how many drivers do free_irq() in
> softirq/tasklet context ...
free_irq()'s /proc fiddling has always been a pain - we just shouldn't be
doing filesystem things in irq/bh context.
> Andrew, this needs to be resolved before v2.6.16, correct? Steve's patch
> solves a real bug in the upstream kernel.
It's not a very big bug - I think only Steve hit it, and that with a
stress-test which was somewhat tuned to hit it.
So we can afford to sit on the problem for a while, as long as someone is
working on a broader /proc-sanity fix. But nobody will do that.
I wonder if we can just punt the unregister_handler_proc/kfree up to a
keventd callback.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [patch, validator] fix proc_subdir_lock related deadlock
2006-01-25 18:23 ` [patch, validator] fix proc_subdir_lock " Andrew Morton
@ 2006-01-25 20:21 ` Ingo Molnar
2006-01-26 0:02 ` [patch, lock validator] fix proc_inum_lock " Ingo Molnar
1 sibling, 0 replies; 8+ messages in thread
From: Ingo Molnar @ 2006-01-25 20:21 UTC (permalink / raw)
To: Andrew Morton; +Cc: rostedt, linux-kernel, viro
* Andrew Morton <akpm@osdl.org> wrote:
> > to solve this we must either change files_lock to be softirq-safe too
> > (bleh!), or we must forbid remove_proc_entry() use from softirq
> > contexts. Neither is a happy solution - remove_proc_entry() is used
> > within free_irq(), and who knows how many drivers do free_irq() in
> > softirq/tasklet context ...
>
> free_irq()'s /proc fiddling has always been a pain - we just shouldn't
> be doing filesystem things in irq/bh context.
the second patch i sent is quite straightforward.
> > Andrew, this needs to be resolved before v2.6.16, correct? Steve's patch
> > solves a real bug in the upstream kernel.
>
> It's not a very big bug - I think only Steve hit it, and that with a
> stress-test which was somewhat tuned to hit it.
still ...
> So we can afford to sit on the problem for a while, as long as someone
> is working on a broader /proc-sanity fix. But nobody will do that.
>
> I wonder if we can just punt the unregister_handler_proc/kfree up to a
> keventd callback.
i'd rather do the files_lock change i sent, and perhaps add a
WARN_ON_ONCE() to all known places that do a free_irq() from softirq
context.
Ingo
^ permalink raw reply [flat|nested] 8+ messages in thread
* [patch, lock validator] fix proc_inum_lock related deadlock
2006-01-25 18:23 ` [patch, validator] fix proc_subdir_lock " Andrew Morton
2006-01-25 20:21 ` Ingo Molnar
@ 2006-01-26 0:02 ` Ingo Molnar
2006-01-26 0:11 ` Ingo Molnar
1 sibling, 1 reply; 8+ messages in thread
From: Ingo Molnar @ 2006-01-26 0:02 UTC (permalink / raw)
To: Andrew Morton; +Cc: rostedt, linux-kernel, viro
there's another VFS lock that just popped up, hopefully the last one.
Fix below. (All this is still related to proc_subdir_lock, and the
original BKL bug it fixed.)
Ingo
-------------
&proc_inum_lock also nests within proc_subdir_lock, and &proc_inum_lock
is used in a softirq-unsafe manner. The lock validator noticed the
following scenario:
=====================================
[ BUG: lock inversion bug detected! ]
-------------------------------------
ifup-eth/2308 just changed the state of lock {proc_subdir_lock} at:
[<c0197083>] remove_proc_entry+0x33/0x1f0
but this lock took lock {proc_inum_lock} in the past, acquired at:
[<c0196fee>] free_proc_entry+0x2e/0x90
and interrupts could create an inverse lock dependency between them,
which could lead to deadlocks!
other info that might help in debugging this:
locks held by ifup-eth/2308:
[<c010432d>] show_trace+0xd/0x10
[<c0104347>] dump_stack+0x17/0x20
[<c0137a41>] check_no_lock_2_mask+0x131/0x180
[<c013852b>] mark_lock+0xfb/0x2a0
[<c0138b63>] debug_lock_chain+0x493/0xdc0
[<c01394cd>] debug_lock_chain_spin+0x3d/0x60
[<c026594d>] _raw_spin_lock+0x2d/0x90
[<c04d91a2>] _spin_lock_bh+0x12/0x20
[<c0197083>] remove_proc_entry+0x33/0x1f0
[<c01429e9>] unregister_handler_proc+0x19/0x20
[<c01421ab>] free_irq+0x7b/0xe0
[<c02f25b2>] floppy_release_irq_and_dma+0x1b2/0x210
[<c02f0aa7>] set_dor+0xc7/0x1b0
[<c02f3b21>] motor_off_callback+0x21/0x30
[<c01274d5>] run_timer_softirq+0xf5/0x1f0
[<c0122e27>] __do_softirq+0x97/0x130
[<c0105519>] do_softirq+0x69/0x100
=======================
the fix is to take proc_inum_lock in a softirq-safe manner.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
----
fs/proc/generic.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
Index: linux/fs/proc/generic.c
===================================================================
--- linux.orig/fs/proc/generic.c
+++ linux/fs/proc/generic.c
@@ -329,9 +329,9 @@ retry:
if (idr_pre_get(&proc_inum_idr, GFP_KERNEL) == 0)
return 0;
- spin_lock(&proc_inum_lock);
+ spin_lock_bh(&proc_inum_lock);
error = idr_get_new(&proc_inum_idr, NULL, &i);
- spin_unlock(&proc_inum_lock);
+ spin_unlock_bh(&proc_inum_lock);
if (error == -EAGAIN)
goto retry;
else if (error)
@@ -350,9 +350,9 @@ static void release_inode_number(unsigne
{
int id = (inum - PROC_DYNAMIC_FIRST) | ~MAX_ID_MASK;
- spin_lock(&proc_inum_lock);
+ spin_lock_bh(&proc_inum_lock);
idr_remove(&proc_inum_idr, id);
- spin_unlock(&proc_inum_lock);
+ spin_unlock_bh(&proc_inum_lock);
}
static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [patch, lock validator] fix proc_inum_lock related deadlock
2006-01-26 0:02 ` [patch, lock validator] fix proc_inum_lock " Ingo Molnar
@ 2006-01-26 0:11 ` Ingo Molnar
0 siblings, 0 replies; 8+ messages in thread
From: Ingo Molnar @ 2006-01-26 0:11 UTC (permalink / raw)
To: Andrew Morton; +Cc: rostedt, linux-kernel, viro
* Ingo Molnar <mingo@elte.hu> wrote:
> there's another VFS lock that just popped up, hopefully the last one.
> Fix below. (All this is still related to proc_subdir_lock, and the
> original BKL bug it fixed.)
bah. proc_num_idr.lock nests too ...
i guess we should stick this into free_irq():
WARN_ON(in_interrupt());
and be done with it. If all such places are fixed then Steve's fix
becomes complete.
Ingo
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2006-01-26 0:11 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2006-01-25 17:03 [patch, validator] fix proc_subdir_lock related deadlock Ingo Molnar
2006-01-25 17:14 ` Steven Rostedt
2006-01-25 18:08 ` Ingo Molnar
2006-01-25 18:14 ` [patch, validator] fix files_lock " Ingo Molnar
2006-01-25 18:23 ` [patch, validator] fix proc_subdir_lock " Andrew Morton
2006-01-25 20:21 ` Ingo Molnar
2006-01-26 0:02 ` [patch, lock validator] fix proc_inum_lock " Ingo Molnar
2006-01-26 0:11 ` Ingo Molnar
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).