Re: [PATCH 3/4] proc: simplify remove_proc_entry() wrt locking
On Tue, Nov 20, 2007 at 08:08:42PM -0800, Andrew Morton wrote:
> On Fri, 16 Nov 2007 18:10:15 +0300 Alexey Dobriyan <[EMAIL PROTECTED]> wrote:
>
> > We can take proc_subdir_lock for duration of list searching and removing
> > from lists only. It can't hurt -- we can gather any amount of looked up
> > PDEs right after proc_subdir_lock droppage in proc_lookup() anyway.
> > Current code should already deal with this correctly.
> >
> > Also this should make code more undestandable:
> > * original looks like a loop, however, it's a loop with unconditional
> > trailing "break;" -- not loop at all.
> > * more explicit statement that proc_subdir_lock protects only ->subdir
> > lists.
>
> oopses the Vaio.
>
>
> [ 12.595145] BUG: unable to handle kernel NULL pointer dereference at
> virtual address 0030
> [ 12.598487] printing eip: c01a607f *pde =
> [ 12.601795] Oops: [#1] PREEMPT
> [ 12.605101] last sysfs file:
> [ 12.608432] Modules linked in:
> [ 12.611727]
> [ 12.615000] Pid: 1, comm: swapper Not tainted (2.6.24-rc3-mm1 #4)
> [ 12.618345] EIP: 0060:[] EFLAGS: 00010206 CPU: 0
> [ 12.621713] EIP is at remove_proc_entry+0x69/0x16c
> [ 12.625071] EAX: EBX: f726d940 ECX: f726d9bd EDX:
> [ 12.628445] ESI: 0030 EDI: f726d940 EBP: f7841e3c ESP: f7841dcc
> [ 12.631747] DS: 007b ES: 007b FS: GS: SS: 0068
> [ 12.635052] Process swapper (pid: 1, ti=F784 task=F783ED30
> task.ti=F784)
> [ 12.635181] Stack: 0005 f726d9c0 c042747c f7841df0 c0131992 0282
> f7841e1c 0005
> [ 12.638669] 0046 0174 c0138012
>
> [ 12.642173]f783f2e0 f783ed30 f783ed30 c0320d27 0010
> f7841e34 c013a1e4
> [ 12.645623] Call Trace:
> [ 12.652432] [] show_trace_log_lvl+0x12/0x25
> [ 12.655938] [] show_stack_log_lvl+0x8c/0x9e
> [ 12.659333] [] show_registers+0x8a/0x1c0
> [ 12.662755] [] die+0xee/0x1c4
> [ 12.666101] [] do_page_fault+0x405/0x4e1
> [ 12.669427] [] error_code+0x6a/0x70
> [ 12.672700] [] unregister_handler_proc+0x1b/0x1d
> [ 12.675974] [] free_irq+0xb3/0xdc
> [ 12.679227] [] yenta_probe_cb_irq+0xc9/0xd6
> [ 12.682482] [] ti12xx_override+0x12b/0x4c5
> [ 12.685782] [] yenta_probe+0x2b1/0x55d
> [ 12.689042] [] pci_device_probe+0x39/0x5b
> [ 12.692276] [] driver_probe_device+0xd1/0x147
> [ 12.695492] [] __driver_attach+0x6a/0xa1
> [ 12.698666] [] bus_for_each_dev+0x37/0x5c
> [ 12.701783] [] driver_attach+0x14/0x16
> [ 12.704891] [] bus_add_driver+0x7a/0x191
> [ 12.708015] [] driver_register+0x57/0x5c
> [ 12.711095] [] __pci_register_driver+0x56/0x83
> [ 12.714170] [] yenta_socket_init+0x14/0x16
> [ 12.717195] [] kernel_init+0xc5/0x20f
> [ 12.720120] [] kernel_thread_helper+0x7/0x10
> [ 12.723041] ===
> [ 12.725918] INFO: lockdep is turned off.
> [ 12.728813] Code: 75 94 83 c6 38 eb 24 8b 55 f0 89 d9 8b 45 90 e8 ab fe ff
> ff 85 c0 74 0e 8b 43 30 89 df 89 06 c7 43 30 00 00 00 00 8b 36 83 c6 30 <8b>
> 1e 85 db 75 d6 b8 e0 2b 43 c0 e8 ab ab 17 00 85 ff 0f 84 e3
> [ 12.735473] EIP: [] remove_proc_entry+0x69/0x16c SS:ESP
> 0068:f7841dcc
>
> (gdb) l *0xc01a4fdf
> 0xc01a4fdf is in remove_proc_entry (fs/proc/generic.c:698).
> warning: Source file is more recent than executable.
>
> 693 if (!parent && xlate_proc_name(name, , ) != 0)
> 694 return;
> 695 len = strlen(fn);
> 696
> 697 spin_lock(_subdir_lock);
> 698 for (p = >subdir; *p; p=&(*p)->next ) {
> 699 if (!proc_match(len, fn, *p))
> 700 continue;
> 701 de = *p;
> 702 *p = de->next;
703 de->next = NULL;
break;<===
704 }
>
> iirc this is what Andy was hitting.
Doh! this was missing "break;". I'll resend the patch and refcounting fixes
soon.
P.S.: Do you make notches on Vaio-of-death?
-
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Re: [PATCH 3/4] proc: simplify remove_proc_entry() wrt locking
On Tue, Nov 20, 2007 at 08:08:42PM -0800, Andrew Morton wrote:
On Fri, 16 Nov 2007 18:10:15 +0300 Alexey Dobriyan [EMAIL PROTECTED] wrote:
We can take proc_subdir_lock for duration of list searching and removing
from lists only. It can't hurt -- we can gather any amount of looked up
PDEs right after proc_subdir_lock droppage in proc_lookup() anyway.
Current code should already deal with this correctly.
Also this should make code more undestandable:
* original looks like a loop, however, it's a loop with unconditional
trailing break; -- not loop at all.
* more explicit statement that proc_subdir_lock protects only -subdir
lists.
oopses the Vaio.
[ 12.595145] BUG: unable to handle kernel NULL pointer dereference at
virtual address 0030
[ 12.598487] printing eip: c01a607f *pde =
[ 12.601795] Oops: [#1] PREEMPT
[ 12.605101] last sysfs file:
[ 12.608432] Modules linked in:
[ 12.611727]
[ 12.615000] Pid: 1, comm: swapper Not tainted (2.6.24-rc3-mm1 #4)
[ 12.618345] EIP: 0060:[c01a607f] EFLAGS: 00010206 CPU: 0
[ 12.621713] EIP is at remove_proc_entry+0x69/0x16c
[ 12.625071] EAX: EBX: f726d940 ECX: f726d9bd EDX:
[ 12.628445] ESI: 0030 EDI: f726d940 EBP: f7841e3c ESP: f7841dcc
[ 12.631747] DS: 007b ES: 007b FS: GS: SS: 0068
[ 12.635052] Process swapper (pid: 1, ti=F784 task=F783ED30
task.ti=F784)
[ 12.635181] Stack: 0005 f726d9c0 c042747c f7841df0 c0131992 0282
f7841e1c 0005
[ 12.638669] 0046 0174 c0138012
[ 12.642173]f783f2e0 f783ed30 f783ed30 c0320d27 0010
f7841e34 c013a1e4
[ 12.645623] Call Trace:
[ 12.652432] [c0104e0c] show_trace_log_lvl+0x12/0x25
[ 12.655938] [c0104eab] show_stack_log_lvl+0x8c/0x9e
[ 12.659333] [c0104f47] show_registers+0x8a/0x1c0
[ 12.662755] [c010516b] die+0xee/0x1c4
[ 12.666101] [c0117a18] do_page_fault+0x405/0x4e1
[ 12.669427] [c0320fda] error_code+0x6a/0x70
[ 12.672700] [c0151d13] unregister_handler_proc+0x1b/0x1d
[ 12.675974] [c0150bb2] free_irq+0xb3/0xdc
[ 12.679227] [c028a51b] yenta_probe_cb_irq+0xc9/0xd6
[ 12.682482] [c028a829] ti12xx_override+0x12b/0x4c5
[ 12.685782] [c028b270] yenta_probe+0x2b1/0x55d
[ 12.689042] [c01fed0d] pci_device_probe+0x39/0x5b
[ 12.692276] [c025a9ad] driver_probe_device+0xd1/0x147
[ 12.695492] [c025ab37] __driver_attach+0x6a/0xa1
[ 12.698666] [c0259ee9] bus_for_each_dev+0x37/0x5c
[ 12.701783] [c025a816] driver_attach+0x14/0x16
[ 12.704891] [c025a220] bus_add_driver+0x7a/0x191
[ 12.708015] [c025ad08] driver_register+0x57/0x5c
[ 12.711095] [c01fee6f] __pci_register_driver+0x56/0x83
[ 12.714170] [c047203c] yenta_socket_init+0x14/0x16
[ 12.717195] [c0458650] kernel_init+0xc5/0x20f
[ 12.720120] [c0104aaf] kernel_thread_helper+0x7/0x10
[ 12.723041] ===
[ 12.725918] INFO: lockdep is turned off.
[ 12.728813] Code: 75 94 83 c6 38 eb 24 8b 55 f0 89 d9 8b 45 90 e8 ab fe ff
ff 85 c0 74 0e 8b 43 30 89 df 89 06 c7 43 30 00 00 00 00 8b 36 83 c6 30 8b
1e 85 db 75 d6 b8 e0 2b 43 c0 e8 ab ab 17 00 85 ff 0f 84 e3
[ 12.735473] EIP: [c01a607f] remove_proc_entry+0x69/0x16c SS:ESP
0068:f7841dcc
(gdb) l *0xc01a4fdf
0xc01a4fdf is in remove_proc_entry (fs/proc/generic.c:698).
warning: Source file is more recent than executable.
693 if (!parent xlate_proc_name(name, parent, fn) != 0)
694 return;
695 len = strlen(fn);
696
697 spin_lock(proc_subdir_lock);
698 for (p = parent-subdir; *p; p=(*p)-next ) {
699 if (!proc_match(len, fn, *p))
700 continue;
701 de = *p;
702 *p = de-next;
703 de-next = NULL;
break;===
704 }
iirc this is what Andy was hitting.
Doh! this was missing break;. I'll resend the patch and refcounting fixes
soon.
P.S.: Do you make notches on Vaio-of-death?
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3/4] proc: simplify remove_proc_entry() wrt locking
On Fri, 16 Nov 2007 18:10:15 +0300 Alexey Dobriyan <[EMAIL PROTECTED]> wrote:
> We can take proc_subdir_lock for duration of list searching and removing
> from lists only. It can't hurt -- we can gather any amount of looked up
> PDEs right after proc_subdir_lock droppage in proc_lookup() anyway.
> Current code should already deal with this correctly.
>
> Also this should make code more undestandable:
> * original looks like a loop, however, it's a loop with unconditional
> trailing "break;" -- not loop at all.
> * more explicit statement that proc_subdir_lock protects only ->subdir lists.
oopses the Vaio.
[ 12.595145] BUG: unable to handle kernel NULL pointer dereference at virtual
address 0030
[ 12.598487] printing eip: c01a607f *pde =
[ 12.601795] Oops: [#1] PREEMPT
[ 12.605101] last sysfs file:
[ 12.608432] Modules linked in:
[ 12.611727]
[ 12.615000] Pid: 1, comm: swapper Not tainted (2.6.24-rc3-mm1 #4)
[ 12.618345] EIP: 0060:[] EFLAGS: 00010206 CPU: 0
[ 12.621713] EIP is at remove_proc_entry+0x69/0x16c
[ 12.625071] EAX: EBX: f726d940 ECX: f726d9bd EDX:
[ 12.628445] ESI: 0030 EDI: f726d940 EBP: f7841e3c ESP: f7841dcc
[ 12.631747] DS: 007b ES: 007b FS: GS: SS: 0068
[ 12.635052] Process swapper (pid: 1, ti=F784 task=F783ED30
task.ti=F784)
[ 12.635181] Stack: 0005 f726d9c0 c042747c f7841df0 c0131992 0282
f7841e1c 0005
[ 12.638669] 0046 0174 c0138012
[ 12.642173]f783f2e0 f783ed30 f783ed30 c0320d27 0010
f7841e34 c013a1e4
[ 12.645623] Call Trace:
[ 12.652432] [] show_trace_log_lvl+0x12/0x25
[ 12.655938] [] show_stack_log_lvl+0x8c/0x9e
[ 12.659333] [] show_registers+0x8a/0x1c0
[ 12.662755] [] die+0xee/0x1c4
[ 12.666101] [] do_page_fault+0x405/0x4e1
[ 12.669427] [] error_code+0x6a/0x70
[ 12.672700] [] unregister_handler_proc+0x1b/0x1d
[ 12.675974] [] free_irq+0xb3/0xdc
[ 12.679227] [] yenta_probe_cb_irq+0xc9/0xd6
[ 12.682482] [] ti12xx_override+0x12b/0x4c5
[ 12.685782] [] yenta_probe+0x2b1/0x55d
[ 12.689042] [] pci_device_probe+0x39/0x5b
[ 12.692276] [] driver_probe_device+0xd1/0x147
[ 12.695492] [] __driver_attach+0x6a/0xa1
[ 12.698666] [] bus_for_each_dev+0x37/0x5c
[ 12.701783] [] driver_attach+0x14/0x16
[ 12.704891] [] bus_add_driver+0x7a/0x191
[ 12.708015] [] driver_register+0x57/0x5c
[ 12.711095] [] __pci_register_driver+0x56/0x83
[ 12.714170] [] yenta_socket_init+0x14/0x16
[ 12.717195] [] kernel_init+0xc5/0x20f
[ 12.720120] [] kernel_thread_helper+0x7/0x10
[ 12.723041] ===
[ 12.725918] INFO: lockdep is turned off.
[ 12.728813] Code: 75 94 83 c6 38 eb 24 8b 55 f0 89 d9 8b 45 90 e8 ab fe ff
ff 85 c0 74 0e 8b 43 30 89 df 89 06 c7 43 30 00 00 00 00 8b 36 83 c6 30 <8b> 1e
85 db 75 d6 b8 e0 2b 43 c0 e8 ab ab 17 00 85 ff 0f 84 e3
[ 12.735473] EIP: [] remove_proc_entry+0x69/0x16c SS:ESP
0068:f7841dcc
(gdb) l *0xc01a4fdf
0xc01a4fdf is in remove_proc_entry (fs/proc/generic.c:698).
warning: Source file is more recent than executable.
693 if (!parent && xlate_proc_name(name, , ) != 0)
694 return;
695 len = strlen(fn);
696
697 spin_lock(_subdir_lock);
698 for (p = >subdir; *p; p=&(*p)->next ) {
699 if (!proc_match(len, fn, *p))
700 continue;
701 de = *p;
702 *p = de->next;
iirc this is what Andy was hitting.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3/4] proc: simplify remove_proc_entry() wrt locking
On Fri, 16 Nov 2007 18:10:15 +0300 Alexey Dobriyan [EMAIL PROTECTED] wrote:
We can take proc_subdir_lock for duration of list searching and removing
from lists only. It can't hurt -- we can gather any amount of looked up
PDEs right after proc_subdir_lock droppage in proc_lookup() anyway.
Current code should already deal with this correctly.
Also this should make code more undestandable:
* original looks like a loop, however, it's a loop with unconditional
trailing break; -- not loop at all.
* more explicit statement that proc_subdir_lock protects only -subdir lists.
oopses the Vaio.
[ 12.595145] BUG: unable to handle kernel NULL pointer dereference at virtual
address 0030
[ 12.598487] printing eip: c01a607f *pde =
[ 12.601795] Oops: [#1] PREEMPT
[ 12.605101] last sysfs file:
[ 12.608432] Modules linked in:
[ 12.611727]
[ 12.615000] Pid: 1, comm: swapper Not tainted (2.6.24-rc3-mm1 #4)
[ 12.618345] EIP: 0060:[c01a607f] EFLAGS: 00010206 CPU: 0
[ 12.621713] EIP is at remove_proc_entry+0x69/0x16c
[ 12.625071] EAX: EBX: f726d940 ECX: f726d9bd EDX:
[ 12.628445] ESI: 0030 EDI: f726d940 EBP: f7841e3c ESP: f7841dcc
[ 12.631747] DS: 007b ES: 007b FS: GS: SS: 0068
[ 12.635052] Process swapper (pid: 1, ti=F784 task=F783ED30
task.ti=F784)
[ 12.635181] Stack: 0005 f726d9c0 c042747c f7841df0 c0131992 0282
f7841e1c 0005
[ 12.638669] 0046 0174 c0138012
[ 12.642173]f783f2e0 f783ed30 f783ed30 c0320d27 0010
f7841e34 c013a1e4
[ 12.645623] Call Trace:
[ 12.652432] [c0104e0c] show_trace_log_lvl+0x12/0x25
[ 12.655938] [c0104eab] show_stack_log_lvl+0x8c/0x9e
[ 12.659333] [c0104f47] show_registers+0x8a/0x1c0
[ 12.662755] [c010516b] die+0xee/0x1c4
[ 12.666101] [c0117a18] do_page_fault+0x405/0x4e1
[ 12.669427] [c0320fda] error_code+0x6a/0x70
[ 12.672700] [c0151d13] unregister_handler_proc+0x1b/0x1d
[ 12.675974] [c0150bb2] free_irq+0xb3/0xdc
[ 12.679227] [c028a51b] yenta_probe_cb_irq+0xc9/0xd6
[ 12.682482] [c028a829] ti12xx_override+0x12b/0x4c5
[ 12.685782] [c028b270] yenta_probe+0x2b1/0x55d
[ 12.689042] [c01fed0d] pci_device_probe+0x39/0x5b
[ 12.692276] [c025a9ad] driver_probe_device+0xd1/0x147
[ 12.695492] [c025ab37] __driver_attach+0x6a/0xa1
[ 12.698666] [c0259ee9] bus_for_each_dev+0x37/0x5c
[ 12.701783] [c025a816] driver_attach+0x14/0x16
[ 12.704891] [c025a220] bus_add_driver+0x7a/0x191
[ 12.708015] [c025ad08] driver_register+0x57/0x5c
[ 12.711095] [c01fee6f] __pci_register_driver+0x56/0x83
[ 12.714170] [c047203c] yenta_socket_init+0x14/0x16
[ 12.717195] [c0458650] kernel_init+0xc5/0x20f
[ 12.720120] [c0104aaf] kernel_thread_helper+0x7/0x10
[ 12.723041] ===
[ 12.725918] INFO: lockdep is turned off.
[ 12.728813] Code: 75 94 83 c6 38 eb 24 8b 55 f0 89 d9 8b 45 90 e8 ab fe ff
ff 85 c0 74 0e 8b 43 30 89 df 89 06 c7 43 30 00 00 00 00 8b 36 83 c6 30 8b 1e
85 db 75 d6 b8 e0 2b 43 c0 e8 ab ab 17 00 85 ff 0f 84 e3
[ 12.735473] EIP: [c01a607f] remove_proc_entry+0x69/0x16c SS:ESP
0068:f7841dcc
(gdb) l *0xc01a4fdf
0xc01a4fdf is in remove_proc_entry (fs/proc/generic.c:698).
warning: Source file is more recent than executable.
693 if (!parent xlate_proc_name(name, parent, fn) != 0)
694 return;
695 len = strlen(fn);
696
697 spin_lock(proc_subdir_lock);
698 for (p = parent-subdir; *p; p=(*p)-next ) {
699 if (!proc_match(len, fn, *p))
700 continue;
701 de = *p;
702 *p = de-next;
iirc this is what Andy was hitting.
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
