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authorThomas Richter <tmricht@linux.ibm.com>2019-07-24 14:27:03 +0200
committerArnaldo Carvalho de Melo <acme@redhat.com>2019-08-08 15:41:25 -0300
commitb9c0a64901d5bdec6eafd38d1dc8fa0e2974fccb (patch)
treea3ad811e38b86f47f7d65ebd62a917c185ae5825 /tools
parent12a6d2940b5f02b4b9f71ce098e3bb02bc24a9ea (diff)
downloadlinux-b9c0a64901d5bdec6eafd38d1dc8fa0e2974fccb.tar.bz2
perf annotate: Fix s390 gap between kernel end and module start
During execution of command 'perf top' the error message: Not enough memory for annotating '__irf_end' symbol!) is emitted from this call sequence: __cmd_top perf_top__mmap_read perf_top__mmap_read_idx perf_event__process_sample hist_entry_iter__add hist_iter__top_callback perf_top__record_precise_ip hist_entry__inc_addr_samples symbol__inc_addr_samples symbol__get_annotation symbol__alloc_hist In this function the size of symbol __irf_end is calculated. The size of a symbol is the difference between its start and end address. When the symbol was read the first time, its start and end was set to: symbol__new: __irf_end 0xe954d0-0xe954d0 which is correct and maps with /proc/kallsyms: root@s8360046:~/linux-4.15.0/tools/perf# fgrep _irf_end /proc/kallsyms 0000000000e954d0 t __irf_end root@s8360046:~/linux-4.15.0/tools/perf# In function symbol__alloc_hist() the end of symbol __irf_end is symbol__alloc_hist sym:__irf_end start:0xe954d0 end:0x3ff80045a8 which is identical with the first module entry in /proc/kallsyms This results in a symbol size of __irf_req for histogram analyses of 70334140059072 bytes and a malloc() for this requested size fails. The root cause of this is function __dso__load_kallsyms() +-> symbols__fixup_end() Function symbols__fixup_end() enlarges the last symbol in the kallsyms map: # fgrep __irf_end /proc/kallsyms 0000000000e954d0 t __irf_end # to the start address of the first module: # cat /proc/kallsyms | sort | egrep ' [tT] ' .... 0000000000e952d0 T __security_initcall_end 0000000000e954d0 T __initramfs_size 0000000000e954d0 t __irf_end 000003ff800045a8 T fc_get_event_number [scsi_transport_fc] 000003ff800045d0 t store_fc_vport_disable [scsi_transport_fc] 000003ff800046a8 T scsi_is_fc_rport [scsi_transport_fc] 000003ff800046d0 t fc_target_setup [scsi_transport_fc] On s390 the kernel is located around memory address 0x200, 0x10000 or 0x100000, depending on linux version. Modules however start some- where around 0x3ff xxxx xxxx. This is different than x86 and produces a large gap for which histogram allocation fails. Fix this by detecting the kernel's last symbol and do no adjustment for it. Introduce a weak function and handle s390 specifics. Reported-by: Klaus Theurich <klaus.theurich@de.ibm.com> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Hendrik Brueckner <brueckner@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20190724122703.3996-2-tmricht@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/arch/s390/util/machine.c17
-rw-r--r--tools/perf/util/symbol.c7
-rw-r--r--tools/perf/util/symbol.h1
3 files changed, 24 insertions, 1 deletions
diff --git a/tools/perf/arch/s390/util/machine.c b/tools/perf/arch/s390/util/machine.c
index de26b1441a48..c8c86a0c9b79 100644
--- a/tools/perf/arch/s390/util/machine.c
+++ b/tools/perf/arch/s390/util/machine.c
@@ -6,6 +6,7 @@
#include "machine.h"
#include "api/fs/fs.h"
#include "debug.h"
+#include "symbol.h"
int arch__fix_module_text_start(u64 *start, u64 *size, const char *name)
{
@@ -33,3 +34,19 @@ int arch__fix_module_text_start(u64 *start, u64 *size, const char *name)
return 0;
}
+
+/* On s390 kernel text segment start is located at very low memory addresses,
+ * for example 0x10000. Modules are located at very high memory addresses,
+ * for example 0x3ff xxxx xxxx. The gap between end of kernel text segment
+ * and beginning of first module's text segment is very big.
+ * Therefore do not fill this gap and do not assign it to the kernel dso map.
+ */
+void arch__symbols__fixup_end(struct symbol *p, struct symbol *c)
+{
+ if (strchr(p->name, '[') == NULL && strchr(c->name, '['))
+ /* Last kernel symbol mapped to end of page */
+ p->end = roundup(p->end, page_size);
+ else
+ p->end = c->start;
+ pr_debug4("%s sym:%s end:%#lx\n", __func__, p->name, p->end);
+}
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 173f3378aaa0..4efde7879474 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -92,6 +92,11 @@ static int prefix_underscores_count(const char *str)
return tail - str;
}
+void __weak arch__symbols__fixup_end(struct symbol *p, struct symbol *c)
+{
+ p->end = c->start;
+}
+
const char * __weak arch__normalize_symbol_name(const char *name)
{
return name;
@@ -218,7 +223,7 @@ void symbols__fixup_end(struct rb_root_cached *symbols)
curr = rb_entry(nd, struct symbol, rb_node);
if (prev->end == prev->start && prev->end != curr->start)
- prev->end = curr->start;
+ arch__symbols__fixup_end(prev, curr);
}
/* Last entry */
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 12755b42ea93..183f630cb5f1 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -288,6 +288,7 @@ const char *arch__normalize_symbol_name(const char *name);
#define SYMBOL_A 0
#define SYMBOL_B 1
+void arch__symbols__fixup_end(struct symbol *p, struct symbol *c);
int arch__compare_symbol_names(const char *namea, const char *nameb);
int arch__compare_symbol_names_n(const char *namea, const char *nameb,
unsigned int n);