[PATCH 1/1] Char: isicom, fix card locking
Could you test this one and turn on lock debugging?
(It's applicable instead of the last one.)
--
isicom, fix card locking
- Somebody omitted spin_unlock in interrupt handler and hence card causes
deadlock. Add two unlocks, before returning from handler, if the lock was
acquired before.
- Recursive locking causes deadlock, fix this by avoiding recursion.
Thanks Eric Fox <[EMAIL PROTECTED]> for pointing these out.
Signed-off-by: Jiri Slaby <[EMAIL PROTECTED]>
---
commit d1cf4c06710e37fee58dbca38e08b236ba8ff50c
tree da27dc848eb073662174276ab7e0472c9da4193c
parent 1240cd642c42688fab680d1d783eb1821ded9490
author Jiri Slaby <[EMAIL PROTECTED]> Thu, 07 Dec 2006 17:42:51 +0059
committer Jiri Slaby <[EMAIL PROTECTED]> Thu, 07 Dec 2006 17:42:51 +0059
drivers/char/isicom.c | 90 ++---
1 files changed, 47 insertions(+), 43 deletions(-)
diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 1637c1d..adbb16d 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -228,6 +228,20 @@ static struct isi_port isi_ports[PORT_C
* it wants to talk.
*/
+static inline int WaitTillCardIsFree(u16 base)
+{
+ unsigned int count = 0;
+ unsigned int a = in_atomic(); /* do we run under spinlock? */
+
+ while (!(inw(base + 0xe) & 0x1) && count++ < 100)
+ if (a)
+ mdelay(1);
+ else
+ msleep(1);
+
+ return !(inw(base + 0xe) & 0x1);
+}
+
static int lock_card(struct isi_board *card)
{
charretries;
@@ -274,69 +288,71 @@ static void unlock_card(struct isi_board
* ISI Card specific ops ...
*/
+/* card->lock HAS to be held */
static void raise_dtr(struct isi_port *port)
{
struct isi_board *card = port->card;
unsigned long base = card->base;
u16 channel = port->channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel << card->shift_count) | 0x02, base);
outw(0x0504, base);
InterruptTheCard(base);
port->status |= ISI_DTR;
- unlock_card(card);
}
+/* card->lock HAS to be held */
static inline void drop_dtr(struct isi_port *port)
{
struct isi_board *card = port->card;
unsigned long base = card->base;
u16 channel = port->channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel << card->shift_count) | 0x02, base);
outw(0x0404, base);
InterruptTheCard(base);
port->status &= ~ISI_DTR;
- unlock_card(card);
}
+/* card->lock HAS to be held */
static inline void raise_rts(struct isi_port *port)
{
struct isi_board *card = port->card;
unsigned long base = card->base;
u16 channel = port->channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel << card->shift_count) | 0x02, base);
outw(0x0a04, base);
InterruptTheCard(base);
port->status |= ISI_RTS;
- unlock_card(card);
}
+
+/* card->lock HAS to be held */
static inline void drop_rts(struct isi_port *port)
{
struct isi_board *card = port->card;
unsigned long base = card->base;
u16 channel = port->channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel << card->shift_count) | 0x02, base);
outw(0x0804, base);
InterruptTheCard(base);
port->status &= ~ISI_RTS;
- unlock_card(card);
}
+/* card->lock MUST NOT be held */
static inline void raise_dtr_rts(struct isi_port *port)
{
struct isi_board *card = port->card;
@@ -353,35 +369,20 @@ static inline void raise_dtr_rts(struct
unlock_card(card);
}
+/* card->lock HAS to be held */
static void drop_dtr_rts(struct isi_port *port)
{
struct isi_board *card = port->card;
unsigned long base = card->base;
u16 channel = port->channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel << card->shift_count) | 0x02, base);
outw(0x0c04, base);
InterruptTheCard(base);
port->status &= ~(ISI_RTS | ISI_DTR);
- unlock_card(card);
-}
-
-static inline void kill_queue(struct isi_port *port, short queue)
-{
- struct isi_board *card = port->card;
- unsigned long base = card->base;
- u16 channel = port->channel;
-
- if (!lock_card(card))
- return;
-
- outw(0x8000 | (channel << card->shift_count) | 0x02, base);
- outw((queue << 8) | 0x06, base);
- InterruptTheCard(base);
- unlock_card(card);
}
/*
@@ -592,6 +593,7 @@ static irqreturn_t isicom_interrupt(int
ClearInterrupt(base);
else
[PATCH 1/1] Char: isicom, fix card locking
Could you test this one and turn on lock debugging?
(It's applicable instead of the last one.)
--
isicom, fix card locking
- Somebody omitted spin_unlock in interrupt handler and hence card causes
deadlock. Add two unlocks, before returning from handler, if the lock was
acquired before.
- Recursive locking causes deadlock, fix this by avoiding recursion.
Thanks Eric Fox [EMAIL PROTECTED] for pointing these out.
Signed-off-by: Jiri Slaby [EMAIL PROTECTED]
---
commit d1cf4c06710e37fee58dbca38e08b236ba8ff50c
tree da27dc848eb073662174276ab7e0472c9da4193c
parent 1240cd642c42688fab680d1d783eb1821ded9490
author Jiri Slaby [EMAIL PROTECTED] Thu, 07 Dec 2006 17:42:51 +0059
committer Jiri Slaby [EMAIL PROTECTED] Thu, 07 Dec 2006 17:42:51 +0059
drivers/char/isicom.c | 90 ++---
1 files changed, 47 insertions(+), 43 deletions(-)
diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 1637c1d..adbb16d 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -228,6 +228,20 @@ static struct isi_port isi_ports[PORT_C
* it wants to talk.
*/
+static inline int WaitTillCardIsFree(u16 base)
+{
+ unsigned int count = 0;
+ unsigned int a = in_atomic(); /* do we run under spinlock? */
+
+ while (!(inw(base + 0xe) 0x1) count++ 100)
+ if (a)
+ mdelay(1);
+ else
+ msleep(1);
+
+ return !(inw(base + 0xe) 0x1);
+}
+
static int lock_card(struct isi_board *card)
{
charretries;
@@ -274,69 +288,71 @@ static void unlock_card(struct isi_board
* ISI Card specific ops ...
*/
+/* card-lock HAS to be held */
static void raise_dtr(struct isi_port *port)
{
struct isi_board *card = port-card;
unsigned long base = card-base;
u16 channel = port-channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel card-shift_count) | 0x02, base);
outw(0x0504, base);
InterruptTheCard(base);
port-status |= ISI_DTR;
- unlock_card(card);
}
+/* card-lock HAS to be held */
static inline void drop_dtr(struct isi_port *port)
{
struct isi_board *card = port-card;
unsigned long base = card-base;
u16 channel = port-channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel card-shift_count) | 0x02, base);
outw(0x0404, base);
InterruptTheCard(base);
port-status = ~ISI_DTR;
- unlock_card(card);
}
+/* card-lock HAS to be held */
static inline void raise_rts(struct isi_port *port)
{
struct isi_board *card = port-card;
unsigned long base = card-base;
u16 channel = port-channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel card-shift_count) | 0x02, base);
outw(0x0a04, base);
InterruptTheCard(base);
port-status |= ISI_RTS;
- unlock_card(card);
}
+
+/* card-lock HAS to be held */
static inline void drop_rts(struct isi_port *port)
{
struct isi_board *card = port-card;
unsigned long base = card-base;
u16 channel = port-channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel card-shift_count) | 0x02, base);
outw(0x0804, base);
InterruptTheCard(base);
port-status = ~ISI_RTS;
- unlock_card(card);
}
+/* card-lock MUST NOT be held */
static inline void raise_dtr_rts(struct isi_port *port)
{
struct isi_board *card = port-card;
@@ -353,35 +369,20 @@ static inline void raise_dtr_rts(struct
unlock_card(card);
}
+/* card-lock HAS to be held */
static void drop_dtr_rts(struct isi_port *port)
{
struct isi_board *card = port-card;
unsigned long base = card-base;
u16 channel = port-channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel card-shift_count) | 0x02, base);
outw(0x0c04, base);
InterruptTheCard(base);
port-status = ~(ISI_RTS | ISI_DTR);
- unlock_card(card);
-}
-
-static inline void kill_queue(struct isi_port *port, short queue)
-{
- struct isi_board *card = port-card;
- unsigned long base = card-base;
- u16 channel = port-channel;
-
- if (!lock_card(card))
- return;
-
- outw(0x8000 | (channel card-shift_count) | 0x02, base);
- outw((queue 8) | 0x06, base);
- InterruptTheCard(base);
- unlock_card(card);
}
/*
@@ -592,6 +593,7 @@ static irqreturn_t isicom_interrupt(int
ClearInterrupt(base);
else
outw(0x, base+0x04); /* enable interrupts */
Re: [PATCH 1/1] Char: isicom, fix card locking
Eric Fox wrote:
> Patch works if I disable SMP in kernel.
Aha, and it didn't work without the patch with SMP disabled?
> strace setserial -g /dev/ttyM0
> execve("/bin/setserial", ["setserial", "-g", "/dev/ttyM0"], [/* 17 vars
> */]) = 0
> uname({sys="Linux", node="dialin-0.vab.com", ...}) = 0
> brk(0) = 0x804d000
> access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or
> directory)
> open("/etc/ld.so.cache", O_RDONLY) = 3
> fstat64(3, {st_mode=S_IFREG|0644, st_size=19713, ...}) = 0
> old_mmap(NULL, 19713, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7f58000
> close(3)= 0
> open("/lib/tls/libc.so.6", O_RDONLY)= 3
> read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320\36"..., 512) =
> 512
> fstat64(3, {st_mode=S_IFREG|0755, st_size=1454802, ...}) = 0
> old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> 0) = 0xb7f57000
> old_mmap(0x39d000, 1223900, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE,
> 3, 0) = 0x39d000
> old_mmap(0x4c2000, 16384, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x124000) = 0x4c2000
> old_mmap(0x4c6000, 7388, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x4c6000
> close(3)= 0
> old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> 0) = 0xb7f56000
> mprotect(0x4c2000, 4096, PROT_READ) = 0
> mprotect(0x399000, 4096, PROT_READ) = 0
> set_thread_area({entry_number:-1 -> 6, base_addr:0xb7f566c0, limit:1048575,
> seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1,
> seg_not_present:0, 0munmap(0xb7f58000, 19713) = 0
> open("/dev/ttyM0", O_RDWR|O_NONBLOCK) = 3
> ioctl(3, TIOCGSERIAL, 0xbf81c280) = 0
In one of these two there should lie the problem in SMP mode. The latter is OK
(no locking), but the former -- hmm, it gets stuck: I guess, we have a recursive
locking example here (I can see one of many in the driver now):
isicom_open()
{
...
isicom_setup_port()
...
}
isicom_setup_port()
{
...
spin_lock_irqsave(>card_lock, flags);
...
isicom_config_port();
...
spin_unlock_irqrestore(>card_lock, flags);
}
isicom_config_port()
{
...
lock_card()
...
unlock_card()
...
}
lock_card()
{
...
spin_lock_irqsave(>card_lock, card->flags);
...
}
unlock_card()
{
spin_unlock_irqrestore(>card_lock, card->flags);
}
Going to fix these.
thanks,
--
http://www.fi.muni.cz/~xslaby/Jiri Slaby
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E
-
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/
[PATCH 1/1] Char: isicom, fix card locking
Eric Fox wrote:
> Here is what i was able to capture from a terminal logged in to the machine
> with the ISI board:
>
> strace setserial -g /dev/ttyM0
> execve("/bin/setserial", ["setserial", "-g", "/dev/ttyM0"], [/* 17 vars
> */]) = 0
> uname({sys="Linux", node="dialin-0.vab.com", ...}) = 0
> brk(0) = 0x804d000
> access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or
> directory)
> open("/etc/ld.so.cache", O_RDONLY) = 3
> fstat64(3, {st_mode=S_IFREG|0644, st_size=19713, ...}) = 0
> old_mmap(NULL, 19713, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7f05000
> close(3)= 0
> open("/lib/tls/libc.so.6", O_RDONLY)= 3
> read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320\36"..., 512) =
> 512
> fstat64(3, {st_mode=S_IFREG|0755, st_size=1454802, ...}) = 0
> old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> 0) = 0xb7f04000
> old_mmap(0x39d000, 1223900, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE,
> 3, 0) = 0x39d000
> old_mmap(0x4c2000, 16384, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x124000) = 0x4c2000
> old_mmap(0x4c6000, 7388, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x4c6000
> close(3)= 0
> old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> 0) = 0xb7f03000
> mprotect(0x4c2000, 4096, PROT_READ) = 0
> mprotect(0x399000, 4096, PROT_READ) = 0
> set_thread_area({entry_number:-1 -> 6, base_addr:0xb7f036c0, limit:1048575,
> seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1,
> seg_not_present:0, useable:1}) = 0
> munmap(0xb7f05000, 19713) = 0
> open("/dev/ttyM0", O_RDWR|O_NONBLOCK
>
>
> And, here is what I captured using minicom from another machine connected
> to the serial port console of the machine with the ISI board (minicom.cap):
>
> strace setserial -g /dev/ttyM0
> execve("/bin/setserial", ["setserial", "-g", "/dev/ttyM0"], [/* 17 vars
> */]) = 0
> uname({sys="Linux", node="dialin-0.vab.com", ...BUG: soft lockup detected
> on CPU#1!
> [] dump_trace+0x6b/0x1ab
> [] show_trace_log_lvl+0x17/0x2b
> [] __func__.5+0x84c/0x497af
> DWARF2 unwinder stuck at __func__.5+0x84c/0x497af
>
> Leftover inexact backtrace:
>
> [] show_trace+0xf/0x11
> [] dump_stack+0x13/0x15
> [] softlockup_tick+0xa1/0xaf
> [] update_process_times+0x39/0x5c
> [] smp_apic_timer_interrupt+0x8a/0xa2
> [] apic_timer_interrupt+0x1f/0x24
> [] _spin_lock_irqsave+0x16/0x27
> [] lock_card_at_interrupt+0x17/0x47 [isicom]
> [] isicom_tx+0x64/0xe9 [isicom]
> [] isicom_tx+0x0/0xe9 [isicom]
> [] run_timer_softirq+0x112/0x15c
> [] __do_softirq+0x5e/0xba
> [] do_softirq+0x2e/0x32
> [] smp_apic_timer_interrupt+0x8f/0xa2
> [] apic_timer_interrupt+0x1f/0x24
> [] mwait_idle_with_hints+0x34/0x38
> [] mwait_idle+0xc/0x1b
> [] cpu_idle+0x66/0x7b
> ===
> BUG: soft lockup detected on CPU#1!
> [] dump_trace+0x6b/0x1ab
> [] show_trace_log_lvl+0x17/0x2b
> [] __func__.5+0x84c/0x497af
> DWARF2 unwinder stuck at __func__.5+0x84c/0x497af
>
>
> Hope some of this will help.
Certainly, it did, could you test the attached patch?
--
isicom, fix card locking
Somebody omitted spin_unlock in interrupt handler and hence card causes
dead-lock. Add two unlocks, before returning from handler, if the lock was
acquired before.
Thanks Eric Fox <[EMAIL PROTECTED]> for pointing this out.
Signed-off-by: Jiri Slaby <[EMAIL PROTECTED]>
---
commit 09a4c63d32367a615fc42a2e8455e5fd37f9c3ed
tree 2c2a050cbc551021d09a581d5cc16fd6a7934c69
parent e62438630ca37539c8cc1553710bbfaa3cf960a7
author Jiri Slaby <[EMAIL PROTECTED]> Wed, 06 Dec 2006 15:13:18 +0100
committer Jiri Slaby <[EMAIL PROTECTED]> Wed, 06 Dec 2006 15:18:43 +0100
drivers/char/isicom.c |2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 58c955e..c55b359 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -592,6 +592,7 @@ static irqreturn_t isicom_interrupt(int
ClearInterrupt(base);
else
outw(0x, base+0x04); /* enable interrupts */
+ spin_unlock(>card_lock);
return IRQ_HANDLED;
}
@@ -712,6 +713,7 @@ static irqreturn_t isicom_interrupt(int
ClearInterrupt(base);
else
outw(0x, base+0x04); /* enable interrupts */
+ spin_unlock(>card_lock);
return IRQ_HANDLED;
}
-
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Please read the FAQ at http://www.tux.org/lkml/
[PATCH 1/1] Char: isicom, fix card locking
Eric Fox wrote:
Here is what i was able to capture from a terminal logged in to the machine
with the ISI board:
strace setserial -g /dev/ttyM0
execve(/bin/setserial, [setserial, -g, /dev/ttyM0], [/* 17 vars
*/]) = 0
uname({sys=Linux, node=dialin-0.vab.com, ...}) = 0
brk(0) = 0x804d000
access(/etc/ld.so.preload, R_OK) = -1 ENOENT (No such file or
directory)
open(/etc/ld.so.cache, O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=19713, ...}) = 0
old_mmap(NULL, 19713, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7f05000
close(3)= 0
open(/lib/tls/libc.so.6, O_RDONLY)= 3
read(3, \177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320\36..., 512) =
512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1454802, ...}) = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb7f04000
old_mmap(0x39d000, 1223900, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE,
3, 0) = 0x39d000
old_mmap(0x4c2000, 16384, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x124000) = 0x4c2000
old_mmap(0x4c6000, 7388, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x4c6000
close(3)= 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb7f03000
mprotect(0x4c2000, 4096, PROT_READ) = 0
mprotect(0x399000, 4096, PROT_READ) = 0
set_thread_area({entry_number:-1 - 6, base_addr:0xb7f036c0, limit:1048575,
seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1,
seg_not_present:0, useable:1}) = 0
munmap(0xb7f05000, 19713) = 0
open(/dev/ttyM0, O_RDWR|O_NONBLOCK
And, here is what I captured using minicom from another machine connected
to the serial port console of the machine with the ISI board (minicom.cap):
strace setserial -g /dev/ttyM0
execve(/bin/setserial, [setserial, -g, /dev/ttyM0], [/* 17 vars
*/]) = 0
uname({sys=Linux, node=dialin-0.vab.com, ...BUG: soft lockup detected
on CPU#1!
[c01041a3] dump_trace+0x6b/0x1ab
[c010436a] show_trace_log_lvl+0x17/0x2b
[c037ddb1] __func__.5+0x84c/0x497af
DWARF2 unwinder stuck at __func__.5+0x84c/0x497af
Leftover inexact backtrace:
[c010438d] show_trace+0xf/0x11
[c010446c] dump_stack+0x13/0x15
[c0138dca] softlockup_tick+0xa1/0xaf
[c0124bc2] update_process_times+0x39/0x5c
[c0111219] smp_apic_timer_interrupt+0x8a/0xa2
[c0103f0b] apic_timer_interrupt+0x1f/0x24
[c0365437] _spin_lock_irqsave+0x16/0x27
[f882407e] lock_card_at_interrupt+0x17/0x47 [isicom]
[f88241ca] isicom_tx+0x64/0xe9 [isicom]
[f8824166] isicom_tx+0x0/0xe9 [isicom]
[c0124d00] run_timer_softirq+0x112/0x15c
[c0120bd1] __do_softirq+0x5e/0xba
[c0120c5b] do_softirq+0x2e/0x32
[c011121e] smp_apic_timer_interrupt+0x8f/0xa2
[c0103f0b] apic_timer_interrupt+0x1f/0x24
[c0101973] mwait_idle_with_hints+0x34/0x38
[c0101983] mwait_idle+0xc/0x1b
[c010183f] cpu_idle+0x66/0x7b
===
BUG: soft lockup detected on CPU#1!
[c01041a3] dump_trace+0x6b/0x1ab
[c010436a] show_trace_log_lvl+0x17/0x2b
[c037ddb1] __func__.5+0x84c/0x497af
DWARF2 unwinder stuck at __func__.5+0x84c/0x497af
Hope some of this will help.
Certainly, it did, could you test the attached patch?
--
isicom, fix card locking
Somebody omitted spin_unlock in interrupt handler and hence card causes
dead-lock. Add two unlocks, before returning from handler, if the lock was
acquired before.
Thanks Eric Fox [EMAIL PROTECTED] for pointing this out.
Signed-off-by: Jiri Slaby [EMAIL PROTECTED]
---
commit 09a4c63d32367a615fc42a2e8455e5fd37f9c3ed
tree 2c2a050cbc551021d09a581d5cc16fd6a7934c69
parent e62438630ca37539c8cc1553710bbfaa3cf960a7
author Jiri Slaby [EMAIL PROTECTED] Wed, 06 Dec 2006 15:13:18 +0100
committer Jiri Slaby [EMAIL PROTECTED] Wed, 06 Dec 2006 15:18:43 +0100
drivers/char/isicom.c |2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 58c955e..c55b359 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -592,6 +592,7 @@ static irqreturn_t isicom_interrupt(int
ClearInterrupt(base);
else
outw(0x, base+0x04); /* enable interrupts */
+ spin_unlock(card-card_lock);
return IRQ_HANDLED;
}
@@ -712,6 +713,7 @@ static irqreturn_t isicom_interrupt(int
ClearInterrupt(base);
else
outw(0x, base+0x04); /* enable interrupts */
+ spin_unlock(card-card_lock);
return IRQ_HANDLED;
}
-
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Re: [PATCH 1/1] Char: isicom, fix card locking
Eric Fox wrote:
Patch works if I disable SMP in kernel.
Aha, and it didn't work without the patch with SMP disabled?
strace setserial -g /dev/ttyM0
execve(/bin/setserial, [setserial, -g, /dev/ttyM0], [/* 17 vars
*/]) = 0
uname({sys=Linux, node=dialin-0.vab.com, ...}) = 0
brk(0) = 0x804d000
access(/etc/ld.so.preload, R_OK) = -1 ENOENT (No such file or
directory)
open(/etc/ld.so.cache, O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=19713, ...}) = 0
old_mmap(NULL, 19713, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7f58000
close(3)= 0
open(/lib/tls/libc.so.6, O_RDONLY)= 3
read(3, \177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320\36..., 512) =
512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1454802, ...}) = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb7f57000
old_mmap(0x39d000, 1223900, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE,
3, 0) = 0x39d000
old_mmap(0x4c2000, 16384, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x124000) = 0x4c2000
old_mmap(0x4c6000, 7388, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x4c6000
close(3)= 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb7f56000
mprotect(0x4c2000, 4096, PROT_READ) = 0
mprotect(0x399000, 4096, PROT_READ) = 0
set_thread_area({entry_number:-1 - 6, base_addr:0xb7f566c0, limit:1048575,
seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1,
seg_not_present:0, 0munmap(0xb7f58000, 19713) = 0
open(/dev/ttyM0, O_RDWR|O_NONBLOCK) = 3
ioctl(3, TIOCGSERIAL, 0xbf81c280) = 0
In one of these two there should lie the problem in SMP mode. The latter is OK
(no locking), but the former -- hmm, it gets stuck: I guess, we have a recursive
locking example here (I can see one of many in the driver now):
isicom_open()
{
...
isicom_setup_port()
...
}
isicom_setup_port()
{
...
spin_lock_irqsave(card-card_lock, flags);
...
isicom_config_port();
...
spin_unlock_irqrestore(card-card_lock, flags);
}
isicom_config_port()
{
...
lock_card()
...
unlock_card()
...
}
lock_card()
{
...
spin_lock_irqsave(card-card_lock, card-flags);
...
}
unlock_card()
{
spin_unlock_irqrestore(card-card_lock, card-flags);
}
Going to fix these.
thanks,
--
http://www.fi.muni.cz/~xslaby/Jiri Slaby
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E
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