From: Sasha Levin <sasha.levin@oracle.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
John Stultz <john.stultz@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Dave Jones <davej@redhat.com>,
Andrey Ryabinin <a.ryabinin@samsung.com>
Subject: sched, timers: use after free in __lock_task_sighand when exiting a process
Date: Sun, 13 Jul 2014 17:51:09 -0400 [thread overview]
Message-ID: <53C2FF4D.3020606@oracle.com> (raw)
Hi all,
While fuzzing with trinity inside a KVM tools guest running the latest -next
kernel with the KASAN patchset, I've stumbled on the following spew:
[ 4838.503887] ==================================================================
[ 4838.510906] AddressSanitizer: use after free in do_raw_spin_lock+0x157/0x240 at addr ffff8800ac3af608
[ 4838.513433] page:ffffea0002b0ebc0 count:0 mapcount:0 mapping: (null) index:0x0
[ 4838.513433] page flags: 0x1fffff80008000(tail)
[ 4838.513433] page dumped because: kasan error
[ 4838.513433] CPU: 14 PID: 19619 Comm: trinity-c52 Tainted: G W 3.16.0-rc4-next-20140711-sasha-00046-g07d3099-dirty #813
[ 4838.513433] 00000000000000fb 0000000000000000 ffffea0002b0ebc0 ffff8805f2e03bc8
[ 4838.513433] ffffffff9ee47068 ffff8805f2e03c98 ffff8805f2e03c88 ffffffff9a426f5c
[ 4838.513433] ffff8805f2fe2d80 ffff8805f2fe2d90 ffff8805f2fe2d80 ffff8805f2fe2d88
[ 4838.513433] Call Trace:
[ 4838.513433] <IRQ> dump_stack (lib/dump_stack.c:52)
[ 4838.513433] kasan_report_error (mm/kasan/report.c:98 mm/kasan/report.c:166)
[ 4838.513433] __asan_load4 (mm/kasan/kasan.c:358)
[ 4838.513433] do_raw_spin_lock (./arch/x86/include/asm/spinlock.h:108 kernel/locking/spinlock_debug.c:112 kernel/locking/spinlock_debug.c:137)
[ 4838.513433] _raw_spin_lock (include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:151)
[ 4838.513433] __lock_task_sighand (kernel/signal.c:1280)
[ 4838.513433] run_posix_cpu_timers (kernel/time/posix-cpu-timers.c:1162)
[ 4838.513433] update_process_times (kernel/time/timer.c:1392)
[ 4838.513433] tick_sched_timer (kernel/time/tick-sched.c:152 kernel/time/tick-sched.c:1096)
[ 4838.513433] __run_hrtimer (kernel/time/hrtimer.c:1272 (discriminator 3))
[ 4838.513433] hrtimer_interrupt (kernel/time/hrtimer.c:1361)
[ 4838.513433] local_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:921)
[ 4838.513433] smp_apic_timer_interrupt (./arch/x86/include/asm/apic.h:696 arch/x86/kernel/apic/apic.c:945)
[ 4838.513433] apic_timer_interrupt (arch/x86/kernel/entry_64.S:1020)
[ 4838.513433] <EOI> ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/paravirt.h:809 include/linux/spinlock_api_smp.h:160 kernel/locking/spinlock.c:191)
[ 4838.513433] __slab_free (include/linux/spinlock.h:358 mm/slub.c:2565)
[ 4838.513433] kmem_cache_free (mm/slub.c:2704 mm/slub.c:2714)
[ 4838.513433] put_io_context (block/blk-ioc.c:154)
[ 4838.513433] put_io_context_active (block/blk-ioc.c:197)
[ 4838.513433] exit_io_context (block/blk-ioc.c:211)
[ 4838.513433] do_exit (kernel/exit.c:801)
[ 4838.513433] do_group_exit (./arch/x86/include/asm/current.h:14 kernel/exit.c:870)
[ 4838.513433] get_signal_to_deliver (kernel/signal.c:2351)
[ 4838.513433] do_signal (arch/x86/kernel/signal.c:698)
[ 4838.513433] do_notify_resume (arch/x86/kernel/signal.c:751)
[ 4838.513433] int_signal (arch/x86/kernel/entry_64.S:600)
[ 4838.513433] Read of size 4 by thread T19619:
[ 4838.513433] Memory state around the buggy address:
[ 4838.513433] ffff8800ac3af380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4838.513433] ffff8800ac3af400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4838.513433] ffff8800ac3af480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4838.513433] ffff8800ac3af500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4838.513433] ffff8800ac3af580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4838.513433] >ffff8800ac3af600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4838.513433] ^
[ 4838.513433] ffff8800ac3af680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4838.513433] ffff8800ac3af700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4838.513433] ffff8800ac3af780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4838.513433] ffff8800ac3af800: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
[ 4838.513433] ffff8800ac3af880: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
[ 4838.513433] ==================================================================
It looks like a race between an exiting process and an external access to it's
'sighand'.
Thanks,
Sasha
next reply other threads:[~2014-07-13 21:52 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-13 21:51 Sasha Levin [this message]
2014-07-13 23:45 ` sched, timers: use after free in __lock_task_sighand when exiting a process Sasha Levin
2014-07-14 9:04 ` Peter Zijlstra
2014-07-14 9:34 ` Andrey Ryabinin
2014-07-14 9:58 ` Peter Zijlstra
2014-07-14 10:25 ` Andrey Ryabinin
2014-07-14 14:49 ` Oleg Nesterov
2014-07-14 15:13 ` Oleg Nesterov
2014-07-14 15:31 ` Andrey Ryabinin
2014-07-14 16:01 ` finish_task_switch && prev_state (Was: sched, timers: use after free in __lock_task_sighand when exiting a process) Oleg Nesterov
2014-07-15 13:12 ` Oleg Nesterov
2014-07-15 13:23 ` Peter Zijlstra
2014-07-15 14:25 ` Oleg Nesterov
2014-07-29 9:10 ` Peter Zijlstra
2014-07-29 9:22 ` Peter Zijlstra
2014-07-29 15:53 ` Oleg Nesterov
2014-07-15 13:28 ` sched, timers: use after free in __lock_task_sighand when exiting a process Peter Zijlstra
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