b9c0a64901
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>
53 lines
1.7 KiB
C
53 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include "util.h"
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#include "machine.h"
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#include "api/fs/fs.h"
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#include "debug.h"
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#include "symbol.h"
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int arch__fix_module_text_start(u64 *start, u64 *size, const char *name)
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{
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u64 m_start = *start;
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char path[PATH_MAX];
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snprintf(path, PATH_MAX, "module/%.*s/sections/.text",
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(int)strlen(name) - 2, name + 1);
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if (sysfs__read_ull(path, (unsigned long long *)start) < 0) {
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pr_debug2("Using module %s start:%#lx\n", path, m_start);
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*start = m_start;
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} else {
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/* Successful read of the modules segment text start address.
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* Calculate difference between module start address
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* in memory and module text segment start address.
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* For example module load address is 0x3ff8011b000
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* (from /proc/modules) and module text segment start
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* address is 0x3ff8011b870 (from file above).
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*
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* Adjust the module size and subtract the GOT table
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* size located at the beginning of the module.
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*/
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*size -= (*start - m_start);
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}
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return 0;
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}
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/* On s390 kernel text segment start is located at very low memory addresses,
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* for example 0x10000. Modules are located at very high memory addresses,
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* for example 0x3ff xxxx xxxx. The gap between end of kernel text segment
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* and beginning of first module's text segment is very big.
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* Therefore do not fill this gap and do not assign it to the kernel dso map.
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*/
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void arch__symbols__fixup_end(struct symbol *p, struct symbol *c)
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{
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if (strchr(p->name, '[') == NULL && strchr(c->name, '['))
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/* Last kernel symbol mapped to end of page */
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p->end = roundup(p->end, page_size);
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else
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p->end = c->start;
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pr_debug4("%s sym:%s end:%#lx\n", __func__, p->name, p->end);
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}
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