[#5253] schedule to CPU0 first would receive signal SIGTRAP when kgdb SMP kernel
Submitted By: Mingquan Pan
Open Date
2009-06-15 03:37:12 Close Date
2009-07-14 04:34:37
Priority:
Medium Assignee:
Sonic Zhang
Status:
Closed Fixed In Release:
N/A
Found In Release:
N/A Release:
Category:
N/A Board:
N/A
Processor:
BF561 Silicon Revision:
Is this bug repeatable?:
Yes Resolution:
Fixed
Uboot version or rev.:
Toolchain version or rev.:
09r1-rc7
App binary format:
N/A
Summary: schedule to CPU0 first would receive signal SIGTRAP when kgdb SMP kernel
Details:
schedule to CPU0 first would receive signal SIGTRAP when kgdb SMP kernel.
when setting break kgdb_test, run cat /proc/kgdbtest on target, the gdb stop at that break point. At this time, do thread 4(CPU1) first or thread 3(CPU0) first would get diffetent results.
Run thread 4 first:
[Switching to Thread 176]
Breakpoint 3, kgdb_test (name=0x10c958 "hello world!", len=12, count=85, z=16) at arch/blackfin/kernel/kgdb_test.c:57
57 printk(KERN_DEBUG "kgdb name(%d): %s, %d, %d\n", len, name, count, z);
(gdb) info thread
* 45 Thread 176 (cat) kgdb_test (name=0x10c958 "hello world!", len=12, count=85, z=16) at arch/blackfin/kernel/kgdb_test.c:57
28 Thread 143 (klogd) 0x0000b114 in resume ()
27 Thread 142 (syslogd) 0x0000b114 in resume ()
26 Thread 141 (inetd) 0x0000b114 in resume ()
25 Thread 140 (sh) 0x0000b114 in resume ()
24 Thread 106 (bfin-spi.0) 0x0000b114 in resume ()
23 Thread 105 (mtdblockd) 0x0000b114 in resume ()
22 Thread 65 (kswapd0) 0x0000b114 in resume ()
21 Thread 64 (pdflush) 0x0000b114 in resume ()
20 Thread 63 (pdflush) 0x0000b114 in resume ()
19 Thread 47 (kblockd/1) 0x0000b114 in resume ()
18 Thread 46 (kblockd/0) 0x0000b114 in resume ()
17 Thread 15 (kstop/1) 0x0000b114 in resume ()
16 Thread 14 (kstop/0) 0x0000b114 in resume ()
15 Thread 11 (khelper) 0x0000b114 in resume ()
14 Thread 10 (events/1) 0x0000b114 in resume ()
13 Thread 9 (events/0) 0x0000b114 in resume ()
12 Thread 8 (watchdog/1) 0x0000b114 in resume ()
11 Thread 7 (ksoftirqd/1) 0x0000b114 in resume ()
10 Thread 6 (migration/1) 0x0000b114 in resume ()
9 Thread 5 (watchdog/0) 0x0000b114 in resume ()
8 Thread 4 (ksoftirqd/0) 0x0000b114 in resume ()
7 Thread 3 (migration/0) 0x0000b114 in resume ()
6 Thread 2 (kthreadd) 0x0000b114 in resume ()
5 Thread 1 (init) 0x0000b114 in resume ()
4 Thread -3 (shadowCPU1) default_idle () at /home/test/work/cruise/checkouts/uclinux-dist/linux-2.6.x/arch/blackfin/include/asm/processor.h:164
3 Thread -2 (shadowCPU0) kgdb_test (name=0x10c958 "hello world!", len=12, count=85, z=16) at arch/blackfin/kernel/kgdb_test.c:57
(gdb) thread 4
[Switching to thread 4 (Thread -3)]#0 kgdb_breakpoint () at kernel/kgdb.c:1796
1796 atomic_set(&kgdb_setting_breakpoint, 0);
(gdb) c
Continuing.
Breakpoint 3, kgdb_test (name=0x10c958 "hello world!", len=12, count=85, z=16) at arch/blackfin/kernel/kgdb_test.c:57
57 printk(KERN_DEBUG "kgdb name(%d): %s, %d, %d\n", len, name, count, z);
(gdb) c
Continuing.
[New Thread 177]
[Switching to Thread 177]
Breakpoint 3, kgdb_test (name=0x10c958 "hello world!", len=12, count=85, z=16) at arch/blackfin/kernel/kgdb_test.c:57
57 printk(KERN_DEBUG "kgdb name(%d): %s, %d, %d\n", len, name, count, z);
Run thread 3 first, it would receive signal SIGTRAP.
(gdb) thread 3
[Switching to thread 3 (Thread -2)]#0 kgdb_test (name=0x10c958 "hello world!", len=12, count=85, z=16) at arch/blackfin/kernel/kgdb_test.c:57
57 printk(KERN_DEBUG "kgdb name(%d): %s, %d, %d\n", len, name, count, z);
(gdb) c
Continuing.
Program received signal SIGTRAP, Trace/breakpoint trap.
[Switching to Thread 177]
0x000099ca in kgdb_test (name=0x10c958 "hello world!", len=12, count=85, z=16) at arch/blackfin/kernel/kgdb_test.c:57
57 printk(KERN_DEBUG "kgdb name(%d): %s, %d, %d\n", len, name, count, z);
(gdb) c
Continuing.
Follow-ups
--- Sonic Zhang 2009-07-01 02:40:48
Fix.
keep cpu switch the same among all cpus, so the context after swith cpu
are the similar to gdb. switch master cpu to itself as well.
--- Mingquan Pan 2009-07-14 04:34:37
Yes,fixed. Close.
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