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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Thomas Richter <tmricht@linux.ibm.com>,
	Hendrik Brueckner <brueckner@linux.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 29/45] perf record: Fix s390 missing module symbol and warning for non-root users
Date: Thu, 20 Jun 2019 19:57:31 +0200	[thread overview]
Message-ID: <20190620174339.036758968@linuxfoundation.org> (raw)
In-Reply-To: <20190620174328.608036501@linuxfoundation.org>

[ Upstream commit 6738028dd57df064b969d8392c943ef3b3ae705d ]

Command 'perf record' and 'perf report' on a system without kernel
debuginfo packages uses /proc/kallsyms and /proc/modules to find
addresses for kernel and module symbols. On x86 this works for root and
non-root users.

On s390, when invoked as non-root user, many of the following warnings
are shown and module symbols are missing:

    proc/{kallsyms,modules} inconsistency while looking for
        "[sha1_s390]" module!

Command 'perf record' creates a list of module start addresses by
parsing the output of /proc/modules and creates a PERF_RECORD_MMAP
record for the kernel and each module. The following function call
sequence is executed:

  machine__create_kernel_maps
    machine__create_module
      modules__parse
        machine__create_module --> for each line in /proc/modules
          arch__fix_module_text_start

Function arch__fix_module_text_start() is s390 specific. It opens
file /sys/module/<name>/sections/.text to extract the module's .text
section start address. On s390 the module loader prepends a header
before the first section, whereas on x86 the module's text section
address is identical the the module's load address.

However module section files are root readable only. For non-root the
read operation fails and machine__create_module() returns an error.
Command perf record does not generate any PERF_RECORD_MMAP record
for loaded modules. Later command perf report complains about missing
module maps.

To fix this function arch__fix_module_text_start() always returns
success. For root users there is no change, for non-root users
the module's load address is used as module's text start address
(the prepended header then counts as part of the text section).

This enable non-root users to use module symbols and avoid the
warning when perf report is executed.

Output before:

  [tmricht@m83lp54 perf]$ ./perf report -D | fgrep MMAP
  0 0x168 [0x50]: PERF_RECORD_MMAP ... x [kernel.kallsyms]_text

Output after:

  [tmricht@m83lp54 perf]$ ./perf report -D | fgrep MMAP
  0 0x168 [0x50]: PERF_RECORD_MMAP ... x [kernel.kallsyms]_text
  0 0x1b8 [0x98]: PERF_RECORD_MMAP ... x /lib/modules/.../autofs4.ko.xz
  0 0x250 [0xa8]: PERF_RECORD_MMAP ... x /lib/modules/.../sha_common.ko.xz
  0 0x2f8 [0x98]: PERF_RECORD_MMAP ... x /lib/modules/.../des_generic.ko.xz

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Link: http://lkml.kernel.org/r/20190522144601.50763-4-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/perf/arch/s390/util/machine.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/perf/arch/s390/util/machine.c b/tools/perf/arch/s390/util/machine.c
index 0b2054007314..a19690a17291 100644
--- a/tools/perf/arch/s390/util/machine.c
+++ b/tools/perf/arch/s390/util/machine.c
@@ -5,16 +5,19 @@
 #include "util.h"
 #include "machine.h"
 #include "api/fs/fs.h"
+#include "debug.h"
 
 int arch__fix_module_text_start(u64 *start, const char *name)
 {
+	u64 m_start = *start;
 	char path[PATH_MAX];
 
 	snprintf(path, PATH_MAX, "module/%.*s/sections/.text",
 				(int)strlen(name) - 2, name + 1);
-
-	if (sysfs__read_ull(path, (unsigned long long *)start) < 0)
-		return -1;
+	if (sysfs__read_ull(path, (unsigned long long *)start) < 0) {
+		pr_debug2("Using module %s start:%#lx\n", path, m_start);
+		*start = m_start;
+	}
 
 	return 0;
 }
-- 
2.20.1




  parent reply	other threads:[~2019-06-20 18:23 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-20 17:57 [PATCH 4.14 00/45] 4.14.129-stable review Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 01/45] perf machine: Guard against NULL in machine__exit() Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 02/45] ax25: fix inconsistent lock state in ax25_destroy_timer Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 03/45] be2net: Fix number of Rx queues used for flow hashing Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 04/45] ipv6: flowlabel: fl6_sock_lookup() must use atomic_inc_not_zero Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 05/45] lapb: fixed leak of control-blocks Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 06/45] neigh: fix use-after-free read in pneigh_get_next Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 07/45] net: openvswitch: do not free vport if register_netdevice() is failed Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 08/45] sctp: Free cookie before we memdup a new one Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 09/45] sunhv: Fix device naming inconsistency between sunhv_console and sunhv_reg Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 10/45] Staging: vc04_services: Fix a couple error codes Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 11/45] perf/x86/intel/ds: Fix EVENT vs. UEVENT PEBS constraints Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 12/45] netfilter: nf_queue: fix reinject verdict handling Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 13/45] ipvs: Fix use-after-free in ip_vs_in Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 14/45] selftests: netfilter: missing error check when setting up veth interface Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 15/45] clk: ti: clkctrl: Fix clkdm_clk handling Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 16/45] powerpc/powernv: Return for invalid IMC domain Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 17/45] mISDN: make sure device name is NUL terminated Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 18/45] x86/CPU/AMD: Dont force the CPB cap when running under a hypervisor Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 19/45] perf/ring_buffer: Fix exposing a temporarily decreased data_head Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 20/45] perf/ring_buffer: Add ordering to rb->nest increment Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 21/45] perf/ring-buffer: Always use {READ,WRITE}_ONCE() for rb->user_page data Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 22/45] gpio: fix gpio-adp5588 build errors Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 23/45] net: tulip: de4x5: Drop redundant MODULE_DEVICE_TABLE() Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 24/45] net: aquantia: fix LRO with FCS error Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 25/45] i2c: dev: fix potential memory leak in i2cdev_ioctl_rdwr Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 26/45] ALSA: hda - Force polling mode on CNL for fixing codec communication Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 27/45] configfs: Fix use-after-free when accessing sd->s_dentry Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 28/45] perf data: Fix strncat may truncate build failure with recent gcc Greg Kroah-Hartman
2019-06-20 17:57 ` Greg Kroah-Hartman [this message]
2019-06-20 17:57 ` [PATCH 4.14 30/45] ia64: fix build errors by exporting paddr_to_nid() Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 31/45] KVM: PPC: Book3S: Use new mutex to synchronize access to rtas token list Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 32/45] KVM: PPC: Book3S HV: Dont take kvm->lock around kvm_for_each_vcpu Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 33/45] net: sh_eth: fix mdio access in sh_eth_close() for R-Car Gen2 and RZ/A1 SoCs Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 34/45] net: phy: dp83867: Set up RGMII TX delay Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 35/45] scsi: libcxgbi: add a check for NULL pointer in cxgbi_check_route() Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 36/45] scsi: smartpqi: properly set both the DMA mask and the coherent DMA mask Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 37/45] scsi: scsi_dh_alua: Fix possible null-ptr-deref Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 38/45] scsi: libsas: delete sas port if expander discover failed Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 39/45] mlxsw: spectrum: Prevent force of 56G Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 40/45] HID: wacom: Dont set tool type until were in range Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 41/45] HID: wacom: Dont report anything prior to the tool entering range Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 42/45] HID: wacom: Send BTN_TOUCH in response to INTUOSP2_BT eraser contact Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 43/45] coredump: fix race condition between collapse_huge_page() and core dumping Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 44/45] infiniband: fix race condition between infiniband mlx4, mlx5 driver " Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 45/45] Abort file_remove_privs() for non-reg. files Greg Kroah-Hartman
2019-06-20 21:51 ` [PATCH 4.14 00/45] 4.14.129-stable review kernelci.org bot
2019-06-21  3:49 ` Naresh Kamboju
2019-06-22  0:44 ` Guenter Roeck

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