From: Laura Abbott <labbott@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>,
Rusty Russell <rusty@rustcorp.com.au>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: 0be964be0 "module: Sanitize RCU usage and locking" breaks symbol_put_addr?
Date: Mon, 17 Aug 2015 16:20:09 -0700 [thread overview]
Message-ID: <55D26C29.5040204@redhat.com> (raw)
Hi,
We received a few bug backtraces:
[ 41.536933] ------------[ cut here ]------------
[ 41.537545] WARNING: CPU: 1 PID: 813 at kernel/module.c:291 module_assert_mutex_or_preempt+0x49/0x90()
[ 41.538174] Modules linked in: mxl5007t af9013 ... dvb_usb_af9015(+) ... dvb_usb_v2 dvb_core rc_core ...
[ 41.542457] CPU: 1 PID: 813 Comm: systemd-udevd Not tainted 4.2.0-0.rc6.git0.1.fc24.x86_64+debug #1
...
[ 41.545938] Call Trace:
[ 41.546607] [<ffffffff81868d8e>] dump_stack+0x4c/0x65
[ 41.547280] [<ffffffff810ab406>] warn_slowpath_common+0x86/0xc0
[ 41.547959] [<ffffffffa057d0b0>] ? af9013_read_ucblocks+0x20/0x20 [af9013]
[ 41.548633] [<ffffffffa057d0b0>] ? af9013_read_ucblocks+0x20/0x20 [af9013]
[ 41.549315] [<ffffffff810ab53a>] warn_slowpath_null+0x1a/0x20
[ 41.549994] [<ffffffff81150529>] module_assert_mutex_or_preempt+0x49/0x90
[ 41.550664] [<ffffffff81150822>] __module_address+0x32/0x150
[ 41.551346] [<ffffffffa057d0b0>] ? af9013_read_ucblocks+0x20/0x20 [af9013]
[ 41.552037] [<ffffffffa057d0b0>] ? af9013_read_ucblocks+0x20/0x20 [af9013]
[ 41.552684] [<ffffffff81150956>] __module_text_address+0x16/0x70
[ 41.553361] [<ffffffffa057d0b0>] ? af9013_read_ucblocks+0x20/0x20 [af9013]
[ 41.554049] [<ffffffffa057d0b0>] ? af9013_read_ucblocks+0x20/0x20 [af9013]
[ 41.554701] [<ffffffff81150f19>] symbol_put_addr+0x29/0x40
[ 41.555392] [<ffffffffa04b77ad>] dvb_frontend_detach+0x7d/0x90 [dvb_core]
[ 41.556078] [<ffffffffa04cdfd5>] dvb_usbv2_probe+0xc85/0x11a0 [dvb_usb_v2]
[ 41.556750] [<ffffffffa05607c4>] af9015_probe+0x84/0xf0 [dvb_usb_af9015]
[ 41.557483] [<ffffffff8161c03b>] usb_probe_interface+0x1bb/0x2e0
[ 41.558169] [<ffffffff81579f26>] driver_probe_device+0x1f6/0x450
[ 41.558837] [<ffffffff8157a214>] __driver_attach+0x94/0xa0
[ 41.559469] [<ffffffff8157a180>] ? driver_probe_device+0x450/0x450
[ 41.560126] [<ffffffff815778f3>] bus_for_each_dev+0x73/0xc0
[ 41.560748] [<ffffffff815796fe>] driver_attach+0x1e/0x20
[ 41.561442] [<ffffffff8157922e>] bus_add_driver+0x1ee/0x280
[ 41.562088] [<ffffffff8157b0a0>] driver_register+0x60/0xe0
[ 41.562712] [<ffffffff8161a87d>] usb_register_driver+0xad/0x160
[ 41.563348] [<ffffffffa0567000>] ? 0xffffffffa0567000
[ 41.563971] [<ffffffffa056701e>] af9015_usb_driver_init+0x1e/0x1000 [dvb_usb_af9015]
[ 41.564580] [<ffffffff81002123>] do_one_initcall+0xb3/0x200
[ 41.565210] [<ffffffff8124ac65>] ? kmem_cache_alloc_trace+0x355/0x380
[ 41.565834] [<ffffffff81867c37>] ? do_init_module+0x28/0x1e9
[ 41.566428] [<ffffffff81867c6f>] do_init_module+0x60/0x1e9
[ 41.567042] [<ffffffff81154167>] load_module+0x21f7/0x28d0
[ 41.567633] [<ffffffff8114f600>] ? m_show+0x1b0/0x1b0
[ 41.568252] [<ffffffff81026d79>] ? sched_clock+0x9/0x10
[ 41.568861] [<ffffffff810e6ddc>] ? local_clock+0x1c/0x20
[ 41.569453] [<ffffffff811549b8>] SyS_init_module+0x178/0x1c0
[ 41.570059] [<ffffffff8187282e>] entry_SYSCALL_64_fastpath+0x12/0x76
[ 41.570630] ---[ end trace 31a9dd90d4f559f5 ]---
Based on my understanding, this is spitting a warning that the module_mutex
isn't held. There's a nice comment in symbol_put_addr right before the call:
/* module_text_address is safe here: we're supposed to have reference
* to module from symbol_get, so it can't go away. */
modaddr = __module_text_address(a);
so it looks like this is an erroneous warning which shouldn't need the mutex held.
Any ideas or am I off base here?
Thanks,
Laura
next reply other threads:[~2015-08-17 23:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-17 23:20 Laura Abbott [this message]
2015-08-18 2:31 ` 0be964be0 "module: Sanitize RCU usage and locking" breaks symbol_put_addr? Peter Zijlstra
2015-08-18 20:49 ` Rusty Russell
2015-08-19 12:42 ` Peter Zijlstra
2015-08-20 1:10 ` Rusty Russell
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