linux, branch v3.4.52

Linux 3.4.52

2013-07-03T18:00:43Z

perf: Fix mmap() accounting hole

2013-07-03T17:59:06Z

commit 9bb5d40cd93c9dd4be74834b1dcb1ba03629716b upstream. Vince's fuzzer once again found holes. This time it spotted a leak in the locked page accounting. When an event had redirected output and its close() was the last reference to the buffer we didn't have a vm context to undo accounting. Change the code to destroy the buffer on the last munmap() and detach all redirected events at that time. This provides us the right context to undo the vm accounting. [Backporting for 3.4-stable. VM_RESERVED flag was replaced with pair 'VM_DONTEXPAND | VM_DONTDUMP' in 314e51b9 since 3.7.0-rc1, and 314e51b9 comes from a big patchset, we didn't backport the patchset, so I restored 'VM_DNOTEXPAND | VM_DONTDUMP' as before: - vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; + vma->vm_flags |= VM_DONTCOPY | VM_RESERVED; -- zliu] Reported-and-tested-by: Vince Weaver Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20130604084421.GI8923@twins.programming.kicks-ass.net Cc: Signed-off-by: Ingo Molnar Signed-off-by: Zhouping Liu Signed-off-by: Greg Kroah-Hartman

perf: Fix perf mmap bugs

2013-07-03T17:59:06Z

commit 26cb63ad11e04047a64309362674bcbbd6a6f246 upstream. Vince reported a problem found by his perf specific trinity fuzzer. Al noticed 2 problems with perf's mmap(): - it has issues against fork() since we use vma->vm_mm for accounting. - it has an rb refcount leak on double mmap(). We fix the issues against fork() by using VM_DONTCOPY; I don't think there's code out there that uses this; we didn't hear about weird accounting problems/crashes. If we do need this to work, the previously proposed VM_PINNED could make this work. Aside from the rb reference leak spotted by Al, Vince's example prog was indeed doing a double mmap() through the use of perf_event_set_output(). This exposes another problem, since we now have 2 events with one buffer, the accounting gets screwy because we account per event. Fix this by making the buffer responsible for its own accounting. [Backporting for 3.4-stable. VM_RESERVED flag was replaced with pair 'VM_DONTEXPAND | VM_DONTDUMP' in 314e51b9 since 3.7.0-rc1, and 314e51b9 comes from a big patchset, we didn't backport the patchset, so I restored 'VM_DNOTEXPAND | VM_DONTDUMP' as before: - vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; + vma->vm_flags |= VM_DONTCOPY | VM_RESERVED; -- zliu] Reported-by: Vince Weaver Signed-off-by: Peter Zijlstra Cc: Al Viro Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Link: http://lkml.kernel.org/r/20130528085548.GA12193@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar Signed-off-by: Zhouping Liu Signed-off-by: Greg Kroah-Hartman

pch_uart: fix a deadlock when pch_uart as console

2013-07-03T17:59:05Z

commit 384e301e3519599b000c1a2ecd938b533fc15d85 upstream. When we use pch_uart as system console like 'console=ttyPCH0,115200', then 'send break' to it. We'll encounter the deadlock on a cpu/core, with interrupts disabled on the core. When we happen to have all irqs affinity to cpu0 then the deadlock on cpu0 actually deadlock whole system. In pch_uart_interrupt, we have spin_lock_irqsave(&priv->lock, flags) then call pch_uart_err_ir when break is received. Then the call to dev_err would actually call to pch_console_write then we'll run into another spin_lock(&priv->lock), with interrupts disabled. So in the call sequence lead by pch_uart_interrupt, we should be carefully to call functions that will 'print message to console' only in case the uart port is not being used as serial console. Signed-off-by: Liang Li Cc: Yijing Wang Signed-off-by: Greg Kroah-Hartman

UBIFS: fix a horrid bug

2013-07-03T17:59:05Z

commit 605c912bb843c024b1ed173dc427cd5c08e5d54d upstream. Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are in the middle of 'ubifs_readdir()'. This means that 'file->private_data' can be freed while 'ubifs_readdir()' uses it, and this is a very bad bug: not only 'ubifs_readdir()' can return garbage, but this may corrupt memory and lead to all kinds of problems like crashes an security holes. This patch fixes the problem by using the 'file->f_version' field, which '->llseek()' always unconditionally sets to zero. We set it to 1 in 'ubifs_readdir()' and whenever we detect that it became 0, we know there was a seek and it is time to clear the state saved in 'file->private_data'. I tested this patch by writing a user-space program which runds readdir and seek in parallell. I could easily crash the kernel without these patches, but could not crash it with these patches. Reported-by: Al Viro Tested-by: Artem Bityutskiy Signed-off-by: Artem Bityutskiy Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

UBIFS: prepare to fix a horrid bug

2013-07-03T17:59:05Z

commit 33f1a63ae84dfd9ad298cf275b8f1887043ced36 upstream. Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are in the middle of 'ubifs_readdir()'. First of all, this means that 'file->private_data' can be freed while 'ubifs_readdir()' uses it. But this particular patch does not fix the problem. This patch is only a preparation, and the fix will follow next. In this patch we make 'ubifs_readdir()' stop using 'file->f_pos' directly, because 'file->f_pos' can be changed by '->llseek()' at any point. This may lead 'ubifs_readdir()' to returning inconsistent data: directory entry names may correspond to incorrect file positions. So here we introduce a local variable 'pos', read 'file->f_pose' once at very the beginning, and then stick to 'pos'. The result of this is that when 'ubifs_dir_llseek()' changes 'file->f_pos' while we are in the middle of 'ubifs_readdir()', the latter "wins". Reported-by: Al Viro Tested-by: Artem Bityutskiy Signed-off-by: Artem Bityutskiy Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

perf: Disable monitoring on setuid processes for regular users

2013-07-03T17:59:04Z

commit 2976b10f05bd7f6dab9f9e7524451ddfed656a89 upstream. There was a a bug in setup_new_exec(), whereby the test to disabled perf monitoring was not correct because the new credentials for the process were not yet committed and therefore the get_dumpable() test was never firing. The patch fixes the problem by moving the perf_event test until after the credentials are committed. Signed-off-by: Stephane Eranian Tested-by: Jiri Olsa Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

dlci: validate the net device in dlci_del()

2013-07-03T17:59:04Z

commit 578a1310f2592ba90c5674bca21c1dbd1adf3f0a upstream. We triggered an oops while running trinity with 3.4 kernel: BUG: unable to handle kernel paging request at 0000000100000d07 IP: [] dlci_ioctl+0xd8/0x2d4 [dlci] PGD 640c0d067 PUD 0 Oops: 0000 [#1] PREEMPT SMP CPU 3 ... Pid: 7302, comm: trinity-child3 Not tainted 3.4.24.09+ 40 Huawei Technologies Co., Ltd. Tecal RH2285 /BC11BTSA RIP: 0010:[] [] dlci_ioctl+0xd8/0x2d4 [dlci] ... Call Trace: [] sock_ioctl+0x153/0x280 [] do_vfs_ioctl+0xa4/0x5e0 [] ? fget_light+0x3ea/0x490 [] sys_ioctl+0x4f/0x80 [] system_call_fastpath+0x16/0x1b ... It's because the net device is not a dlci device. Reported-by: Li Jinyue Signed-off-by: Li Zefan Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

dlci: acquire rtnl_lock before calling __dev_get_by_name()

2013-07-03T17:59:03Z

commit 11eb2645cbf38a08ae491bf6c602eea900ec0bb5 upstream. Otherwise the net device returned can be freed at anytime. Signed-off-by: Li Zefan Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot()

2013-07-03T17:59:01Z

commit c790b0ad23f427c7522ffed264706238c57c007e upstream. fetch_bp_busy_slots() and toggle_bp_slot() use for_each_online_cpu(), this is obviously wrong wrt cpu_up() or cpu_down(), we can over/under account the per-cpu numbers. For example: # echo 0 >> /sys/devices/system/cpu/cpu1/online # perf record -e mem:0x10 -p 1 & # echo 1 >> /sys/devices/system/cpu/cpu1/online # perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10 -C1 -a & # taskset -p 0x2 1 triggers the same WARN_ONCE("Can't find any breakpoint slot") in arch_install_hw_breakpoint(). Reported-by: Vince Weaver Signed-off-by: Oleg Nesterov Acked-by: Frederic Weisbecker Link: http://lkml.kernel.org/r/20130620155009.GA6327@redhat.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman