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Commit c2e4b24f authored by Kapileshwar Singh's avatar Kapileshwar Singh Committed by Arnaldo Carvalho de Melo
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tools lib traceevent: Fix string handling in heterogeneous arch environments 



When a trace recorded on a 32-bit device is processed with a 64-bit
binary, the higher 32-bits of the address need to ignored.

The lack of this results in the output of the 64-bit pointer
value to the trace as the 32-bit address lookup fails in find_printk().

Before:

  burn-1778  [003]   548.600305: bputs:   0xc0046db2s: 2cec5c058d98c

After:

  burn-1778  [003]   548.600305: bputs:   0xc0046db2s: RT throttling activated

The problem occurs in PRINT_FIELD when the field is recognized as a
pointer to a string (of the type const char *)

Heterogeneous architectures cases below can arise and should be handled:

* Traces recorded using 32-bit addresses processed on a 64-bit machine
* Traces recorded using 64-bit addresses processed on a 32-bit machine

Reported-by: default avatarJuri Lelli <juri.lelli@arm.com>
Signed-off-by: default avatarKapileshwar Singh <kapileshwar.singh@arm.com>
Reviewed-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Javi Merino <javi.merino@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1442928123-13824-1-git-send-email-kapileshwar.singh@arm.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 381c02f6

tools/lib/traceevent/event-parse.c

+20 −3
Original line number Diff line number Diff line
@@ -3795,7 +3795,7 @@ static void print_str_arg(struct trace_seq *s, void *data, int size, 
	struct format_field *field;

	struct printk_map *printk;

	long long val, fval;

	unsigned long addr;

	unsigned long long addr;

	char *str;

	unsigned char *hex;

	int print;
@@ -3828,13 +3828,30 @@ static void print_str_arg(struct trace_seq *s, void *data, int size, 
		 */

		if (!(field->flags & FIELD_IS_ARRAY) &&

		    field->size == pevent->long_size) {

			addr = *(unsigned long *)(data + field->offset);



			/* Handle heterogeneous recording and processing

			 * architectures

			 *

			 * CASE I:

			 * Traces recorded on 32-bit devices (32-bit

			 * addressing) and processed on 64-bit devices:

			 * In this case, only 32 bits should be read.

			 *

			 * CASE II:

			 * Traces recorded on 64 bit devices and processed

			 * on 32-bit devices:

			 * In this case, 64 bits must be read.

			 */

			addr = (pevent->long_size == 8) ?

				*(unsigned long long *)(data + field->offset) :

				(unsigned long long)*(unsigned int *)(data + field->offset);



			/* Check if it matches a print format */

			printk = find_printk(pevent, addr);

			if (printk)

				trace_seq_puts(s, printk->printk);

			else

				trace_seq_printf(s, "%lx", addr);

				trace_seq_printf(s, "%llx", addr);

			break;

		}

		str = malloc(len + 1);