On Wed, Jul 22, 2015 at 03:14:42PM +0200, Andrey Konovalov wrote: > Hi! > > We are working on a dynamic data race detector for Linux kernel called > KernelThreadSanitizer (ktsan) (https://github.com/google/ktsan/wiki). > > Here is a report we got while running ktsan (upstream revision > 21bdb584af8cca7c6df3c44cba268be050a234eb). > > ================================================================== > ThreadSanitizer: data-race in psmouse_interrupt > > Write of size 1 by thread T1 (K1): > [<ffffffff819d5272>] psmouse_interrupt+0xd2/0x690 > drivers/input/mouse/psmouse-base.c:337 > [<ffffffff819bcd16>] serio_interrupt+0x66/0xb0 > drivers/input/serio/serio.c:1008 > [<ffffffff819be5f0>] i8042_interrupt+0x240/0x4d0 > drivers/input/serio/i8042.c:541 > [<ffffffff810f03b2>] handle_irq_event_percpu+0x62/0x2a0 > kernel/irq/handle.c:143 > [<ffffffff810f0692>] handle_irq_event+0xa2/0xf0 kernel/irq/handle.c:192 > [<ffffffff810f5414>] handle_edge_irq+0x104/0x380 kernel/irq/chip.c:608 > [< inlined >] handle_irq+0xf6/0x220 generic_handle_irq_desc > include/linux/irqdesc.h:146 > [<ffffffff81009f86>] handle_irq+0xf6/0x220 arch/x86/kernel/irq_64.c:81 > [<ffffffff810093ce>] do_IRQ+0x5e/0x110 arch/x86/kernel/irq.c:223 > [<ffffffff81e726ab>] ret_from_intr+0x0/0x1f arch/x86/entry/entry_64.S:601 > [< inlined >] irq_exit+0x98/0xa0 invoke_softirq kernel/softirq.c:350 > [<ffffffff8108edd8>] irq_exit+0x98/0xa0 kernel/softirq.c:391 > [< inlined >] smp_apic_timer_interrupt+0x63/0x80 exiting_irq > ./arch/x86/include/asm/apic.h:655 > [<ffffffff8105c503>] smp_apic_timer_interrupt+0x63/0x80 > arch/x86/kernel/apic/apic.c:915 > [<ffffffff81e7299b>] apic_timer_interrupt+0x6b/0x70 > arch/x86/entry/entry_64.S:782 > [<ffffffff8153223d>] kvasprintf+0x5d/0x90 lib/kasprintf.c:24 > [<ffffffff815322be>] kasprintf+0x4e/0x70 lib/kasprintf.c:40 > [< inlined >] module_add_driver+0x8f/0x180 make_driver_name > drivers/base/module.c:18 > [<ffffffff8183059f>] module_add_driver+0x8f/0x180 drivers/base/module.c:63 > [<ffffffff81812c94>] bus_add_driver+0x204/0x340 drivers/base/bus.c:713 > [<ffffffff81814e2b>] driver_register+0xdb/0x190 drivers/base/driver.c:168 > [<ffffffff81a5ed16>] __hid_register_driver+0xb6/0x100 > drivers/hid/hid-core.c:2677 > [<ffffffff825ab67d>] apple_driver_init+0x24/0x31 drivers/hid/hid-apple.c:574 > [<ffffffff81000339>] do_one_initcall+0xb9/0x220 init/main.c:798 > [< inlined >] kernel_init_freeable+0x2ca/0x397 > do_initcall_level init/main.c:863 > [< inlined >] kernel_init_freeable+0x2ca/0x397 do_initcalls > init/main.c:871 > [< inlined >] kernel_init_freeable+0x2ca/0x397 do_basic_setup > init/main.c:890 > [<ffffffff8253d919>] kernel_init_freeable+0x2ca/0x397 init/main.c:1013 > [<ffffffff81e5ad66>] kernel_init+0x16/0x140 init/main.c:941 > [<ffffffff81e71f5f>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:526 > DBG: cpu = ffff88053fd9fe68 > DBG: cpu id = 3 > > Previous read of size 1 by thread T509 (K506): > [< inlined >] cypress_send_ext_cmd+0x193/0x500 > cypress_ps2_read_cmd_status drivers/input/mouse/cypress_ps2.c:123 > [<ffffffff819e6b23>] cypress_send_ext_cmd+0x193/0x500 > drivers/input/mouse/cypress_ps2.c:192 > [<ffffffff819e6f5a>] cypress_detect+0x2a/0xb0 > drivers/input/mouse/cypress_ps2.c:208 > [<ffffffff819d5e66>] psmouse_extensions+0x1f6/0x4e0 > drivers/input/mouse/psmouse-base.c:849 (discriminator 1) > [<ffffffff819d63fd>] psmouse_switch_protocol+0x2ad/0x330 > drivers/input/mouse/psmouse-base.c:1467 > [<ffffffff819d7426>] psmouse_connect+0x2e6/0x450 > drivers/input/mouse/psmouse-base.c:1554 (discriminator 4) > [< inlined >] serio_driver_probe+0x57/0x80 > serio_connect_driver drivers/input/serio/serio.c:65 > [<ffffffff819bcf77>] serio_driver_probe+0x57/0x80 > drivers/input/serio/serio.c:796 > [< inlined >] driver_probe_device+0x1da/0x460 really_probe > drivers/base/dd.c:308 > [<ffffffff81813b1a>] driver_probe_device+0x1da/0x460 drivers/base/dd.c:414 > [<ffffffff81813e64>] __driver_attach+0xc4/0xd0 drivers/base/dd.c:612 > [<ffffffff81810933>] bus_for_each_dev+0x93/0xe0 drivers/base/bus.c:314 > [<ffffffff81813353>] driver_attach+0x33/0x50 drivers/base/dd.c:631 > [< inlined >] serio_handle_event+0x2d3/0x3b0 > serio_attach_driver drivers/input/serio/serio.c:826 > [<ffffffff819bd8e3>] serio_handle_event+0x2d3/0x3b0 > drivers/input/serio/serio.c:245 > [<ffffffff810adcf9>] process_one_work+0x2a9/0x6d0 kernel/workqueue.c:2036 > [<ffffffff810aeddf>] worker_thread+0xbf/0x710 kernel/workqueue.c:2170 > [<ffffffff810b700c>] kthread+0x15c/0x180 kernel/kthread.c:207 > [<ffffffff81e71f5f>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:526 > DBG: cpu = 0 > > DBG: addr: ffff88019d703909 > DBG: first offset: 1, second offset: 1 > DBG: T1 clock: {T1: 17075020, T509: 142163} > DBG: T509 clock: {T509: 142167} > ================================================================== > > It seems that accessing 'psmouse->pktcnt' in > 'psmouse->packet[psmouse->pktcnt++] = data' in 'psmouse_interrupt()' > is racing with 'wait_event_timeout(ps2dev->wait, (psmouse->pktcnt >= > pktsize), msecs_to_jiffies(CYTP_CMD_TIMEOUT))' in > 'cypress_ps2_read_cmd_status()'. > If that's the case, it's possible that 'psmouse->pktcnt' is > incremented, but no data is written yet, so '(psmouse->pktcnt >= > pktsize)' will evaluate to true and the following 'memcpy' will access > invalid data. > > Could you confirm if this is a real data race?
Yes, looks like real positive. Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
