NAME
p - print the value of an expression
SYNOPSIS
p [-x|-d][-u] [expression | symbol[:cpuspec]]
DESCRIPTION
This command passes its arguments on to gdb "print" command for evaluation.
expression an expression to be evaluated.
symbol a kernel symbol.
:cpuspec CPU specification for a per-cpu symbol:
: CPU of the currently selected task.
:a[ll] all CPUs.
:#[-#][,...] CPU list(s), e.g. "1,3,5", "1-3",
or "1,3,5-7,10".
-x override default output format with hexadecimal format.
-d override default output format with decimal format.
-u the expression evaluates to a user address reference.
The default output format is decimal, but that can be changed at any time
with the two built-in aliases "hex" and "dec". Alternatively, there
are two other built-in aliases, "px" and "pd", which force the command
output to be displayed in hexadecimal or decimal, without changing the
default mode.
EXAMPLES
Print the contents of jiffies:
crash> p jiffies
jiffies = $6 = 166532620
crash> px jiffies
jiffies = $7 = 0x9ed174b
crash> pd jiffies
jiffies = $8 = 166533160
Print the contents of the vm_area_struct "init_mm":
crash> p init_mm
init_mm = $5 = {
mmap = 0xc022d540,
mmap_avl = 0x0,
mmap_cache = 0x0,
pgd = 0xc0101000,
count = {
counter = 0x6
},
map_count = 0x1,
mmap_sem = {
count = {
counter = 0x1
},
waking = 0x0,
wait = 0x0
},
context = 0x0,
start_code = 0xc0000000,
end_code = 0xc022b4c8,
start_data = 0x0,
end_data = 0xc0250388,
start_brk = 0x0,
brk = 0xc02928d8,
start_stack = 0x0,
arg_start = 0x0,
arg_end = 0x0,
env_start = 0x0,
env_end = 0x0,
rss = 0x0,
total_vm = 0x0,
locked_vm = 0x0,
def_flags = 0x0,
cpu_vm_mask = 0x0,
swap_cnt = 0x0,
swap_address = 0x0,
segments = 0x0
}
If a per-cpu symbol is entered as a argument, its data type
and all of its per-cpu addresses are displayed:
crash> p irq_stat
PER-CPU DATA TYPE:
irq_cpustat_t irq_stat;
PER-CPU ADDRESSES:
[0]: ffff88021e211540
[1]: ffff88021e251540
[2]: ffff88021e291540
[3]: ffff88021e2d1540
To display the contents a per-cpu symbol for CPU 1, append
a cpu-specifier:
crash> p irq_stat:1
per_cpu(irq_stat, 1) = $29 = {
__softirq_pending = 0,
__nmi_count = 209034,
apic_timer_irqs = 597509876,
irq_spurious_count = 0,
icr_read_retry_count = 2,
x86_platform_ipis = 0,
apic_perf_irqs = 209034,
apic_irq_work_irqs = 0,
irq_resched_count = 264922233,
irq_call_count = 7036692,
irq_tlb_count = 4750442,
irq_thermal_count = 0,
irq_threshold_count = 0
}