[#5825] gdb: symbols cannot map to correct source file
Submitted By: Yi Li
Open Date
2010-01-12 08:12:57 Close Date
2010-04-20 07:51:41
Priority:
Medium Assignee:
Jie Zhang
Board:
N/A Silicon Revision:
0.2
Resolution:
Rejected Fixed In Release:
N/A
Processor:
BF537
Host Operating System:
toolchain rev.:
2009r1.1-rc2 gcc 4.1 kernel rev.:
State:
Closed Found In Release:
2009R1.1_RC2
Is this bug repeatable?:
yes
Summary: gdb: symbols cannot map to correct source file
Details:
Tested on BF537-STAMP.
linux-kernel: svn trunk r8145
gcc: bfin-uclinux-gcc 4.1 2009r1.1-2
Detail configuration please see attached bugreport.tgz.
Debug kernel using bfin-elf-gdb, set breakpoint to function "bfin_cs_cycles_init()" (this function is defined in arch/blackfin/kernel/time-ts.c). However, gdb says the break point is set to "include/linux/clocksource.h, line 253."
bfin-elf-gdb vmlinux
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This GDB was configured as "--host=i686-pc-linux-gnu --target=bfin-elf"...
(gdb) b bfin_cs_cycles_init
Breakpoint 1 at 0x195a4c: file include/linux/clocksource.h, line 253.
(gdb)
objdump:
00195a48 <_bfin_cs_cycles_init>:
195a48: ed 05 [--SP] = (R7:5, P5:5);
195a4a: 67 01 [--SP] = RETS;
195a4c: 4d e1 18 00 P5.H = 0x18; /* ( 24) P5=0x1821f8 <_dma_io_base_addr> */
195a50: 66 6f SP += -0x14; /* (-20) */
195a52: 0d e1 dc 18 P5.L = 0x18dc; /* (6364) P5=0x1818dc <_bfin_cs_cycles> */
195a56: f3 e3 eb 62 CALL 0x202c <_get_cclk>;
195a5a: 47 e1 9a 3b R7.H = 0x3b9a; /* (15258) R7=0x3b9a5700(999970560) */
195a5e: ab a2 R3 = [P5 + 0x28];
195a60: 07 e1 00 ca R7.L = 0xca00; /* (-13824) R7=0x3b9aca00(1000000000) */
195a64: 28 30 R5 = R0;
195a66: 0b 30 R1 = R3;
195a68: 42 e1 cd 1d R2.H = 0x1dcd; /* (7629) R2=0x1dcd0002(499974146) */
195a6c: f8 60 R0 = 0x1f (X); /* R0=0x1f( 31) */
195a6e: 01 67 R1 += -0x20; /* (-32) */
195a70: 37 30 R6 = R7;
195a72: 18 52 R0 = R0 - R3;
195a74: 02 e1 00 65 R2.L = 0x6500; /* (25856) R2=0x1dcd6500(500000000) */
However, if I set breakpoint to address "0x195a50", it would be OK.
(gdb) b *0x195a50
Breakpoint 2 at 0x195a50: file arch/blackfin/kernel/time-ts.c, line 72.
(gdb) l *0x195a50
0x195a50 is in bfin_cs_cycles_init (arch/blackfin/kernel/time-ts.c:72).
67 return clocksource_cyc2ns(bfin_read_cycles(&bfin_cs_cycles),
68 bfin_cs_cycles.mult, bfin_cs_cycles.shift);
69 }
70
71 static int __init bfin_cs_cycles_init(void)
72 {
73 bfin_cs_cycles.mult = \
74 clocksource_hz2mult(get_cclk(), bfin_cs_cycles.shift);
75
76 if (clocksource_register(&bfin_cs_cycles))
(gdb) l *0x195a4c
0x195a4c is in bfin_cs_cycles_init (include/linux/clocksource.h:253).
248 * mult = 1000000000 * 2^shift / hz
249 * mult = (1000000000<<shift) / hz
250 */
251 u64 tmp = ((u64)1000000000) << shift_constant;
252
253 tmp += hz/2; /* round for do_div */
254 do_div(tmp, hz);
255
256 return (u32)tmp;
257 }
Do you think GDB is behaving normally?
Follow-ups
--- Yi Li 2010-01-12 08:25:20
I think the situation happens because the first line of bfin_cs_cycles_init() is
an inline function:
static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant)
{
/* hz = cyc/(Billion ns)
* mult/2^shift = ns/cyc
* mult = ns/cyc * 2^shift
* mult = 1Billion/hz * 2^shift
* mult = 1000000000 * 2^shift / hz
* mult = (1000000000<<shift) / hz
*/
u64 tmp = ((u64)1000000000) << shift_constant;
tmp += hz/2; /* round for do_div */
do_div(tmp, hz);
return (u32)tmp;
}
But this is not what expected for breakpoints.
--- Yi Li 2010-01-12 08:58:39
This issue can also happen when the first line of a function is a
"#define" micro. e.g:
(gdb) b trace_hardirqs_on
Breakpoint 5 at 0x47156: file include/trace/events/hist.h, line 13.
kernel/trace/trace_irqsoff.c:
void trace_hardirqs_on(void)
trace_preemptirqsoff_hist(IRQS_ON, 0);
if (!preempt_trace() && irq_trace())
stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
EXPORT_SYMBOL(trace_hardirqs_on);
include/trace/events/hist.h:
#if !defined(CONFIG_PREEMPT_OFF_HIST) &&
!defined(CONFIG_INTERRUPT_OFF_HIST)
#define trace_preemptirqsoff_hist(a,b)
#else
TRACE_EVENT(preemptirqsoff_hist,
...
#endif
--- Jie Zhang 2010-01-12 22:49:16
Both are expected.
--- Robin Getz 2010-04-20 07:49:57
Since this is expected behaviour - marking closed
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