user/sven/linux.git/include, branch v3.10.65

mm: propagate error from stack expansion even for guard page

2015-01-16T14:59:03Z

commit fee7e49d45149fba60156f5b59014f764d3e3728 upstream. Jay Foad reports that the address sanitizer test (asan) sometimes gets confused by a stack pointer that ends up being outside the stack vma that is reported by /proc/maps. This happens due to an interaction between RLIMIT_STACK and the guard page: when we do the guard page check, we ignore the potential error from the stack expansion, which effectively results in a missing guard page, since the expected stack expansion won't have been done. And since /proc/maps explicitly ignores the guard page (commit d7824370e263: "mm: fix up some user-visible effects of the stack guard page"), the stack pointer ends up being outside the reported stack area. This is the minimal patch: it just propagates the error. It also effectively makes the guard page part of the stack limit, which in turn measn that the actual real stack is one page less than the stack limit. Let's see if anybody notices. We could teach acct_stack_growth() to allow an extra page for a grow-up/grow-down stack in the rlimit test, but I don't want to add more complexity if it isn't needed. Reported-and-tested-by: Jay Foad Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

pstore-ram: Allow optional mapping with pgprot_noncached

2015-01-16T14:59:00Z

commit 027bc8b08242c59e19356b4b2c189f2d849ab660 upstream. On some ARMs the memory can be mapped pgprot_noncached() and still be working for atomic operations. As pointed out by Colin Cross , in some cases you do want to use pgprot_noncached() if the SoC supports it to see a debug printk just before a write hanging the system. On ARMs, the atomic operations on strongly ordered memory are implementation defined. So let's provide an optional kernel parameter for configuring pgprot_noncached(), and use pgprot_writecombine() by default. Cc: Arnd Bergmann Cc: Rob Herring Cc: Randy Dunlap Cc: Anton Vorontsov Cc: Colin Cross Cc: Olof Johansson Cc: Russell King Acked-by: Kees Cook Signed-off-by: Tony Lindgren Signed-off-by: Tony Luck Signed-off-by: Greg Kroah-Hartman

userns: Add a knob to disable setgroups on a per user namespace basis

2015-01-08T17:58:16Z

commit 9cc46516ddf497ea16e8d7cb986ae03a0f6b92f8 upstream. - Expose the knob to user space through a proc file /proc//setgroups A value of "deny" means the setgroups system call is disabled in the current processes user namespace and can not be enabled in the future in this user namespace. A value of "allow" means the segtoups system call is enabled. - Descendant user namespaces inherit the value of setgroups from their parents. - A proc file is used (instead of a sysctl) as sysctls currently do not allow checking the permissions at open time. - Writing to the proc file is restricted to before the gid_map for the user namespace is set. This ensures that disabling setgroups at a user namespace level will never remove the ability to call setgroups from a process that already has that ability. A process may opt in to the setgroups disable for itself by creating, entering and configuring a user namespace or by calling setns on an existing user namespace with setgroups disabled. Processes without privileges already can not call setgroups so this is a noop. Prodcess with privilege become processes without privilege when entering a user namespace and as with any other path to dropping privilege they would not have the ability to call setgroups. So this remains within the bounds of what is possible without a knob to disable setgroups permanently in a user namespace. Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

userns: Don't allow setgroups until a gid mapping has been setablished

2015-01-08T17:58:16Z

commit 273d2c67c3e179adb1e74f403d1e9a06e3f841b5 upstream. setgroups is unique in not needing a valid mapping before it can be called, in the case of setgroups(0, NULL) which drops all supplemental groups. The design of the user namespace assumes that CAP_SETGID can not actually be used until a gid mapping is established. Therefore add a helper function to see if the user namespace gid mapping has been established and call that function in the setgroups permission check. This is part of the fix for CVE-2014-8989, being able to drop groups without privilege using user namespaces. Reviewed-by: Andy Lutomirski Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

groups: Consolidate the setgroups permission checks

2015-01-08T17:58:16Z

commit 7ff4d90b4c24a03666f296c3d4878cd39001e81e upstream. Today there are 3 instances of setgroups and due to an oversight their permission checking has diverged. Add a common function so that they may all share the same permission checking code. This corrects the current oversight in the current permission checks and adds a helper to avoid this in the future. A user namespace security fix will update this new helper, shortly. Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

iio: Fix IIO_EVENT_CODE_EXTRACT_DIR bit mask

2014-12-06T23:05:47Z

commit ccf54555da9a5e91e454b909ca6a5303c7d6b910 upstream. The direction field is set on 7 bits, thus we need to AND it with 0111 111 mask in order to retrieve it, that is 0x7F, not 0xCF as it is now. Fixes: ade7ef7ba (staging:iio: Differential channel handling) Signed-off-by: Cristina Ciocan Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman

PCI/MSI: Add device flag indicating that 64-bit MSIs don't work

2014-12-06T23:05:47Z

commit f144d1496b47e7450f41b767d0d91c724c2198bc upstream. This can be set by quirks/drivers to be used by the architecture code that assigns the MSI addresses. We additionally add verification in the core MSI code that the values assigned by the architecture do satisfy the limitation in order to fail gracefully if they don't (ie. the arch hasn't been updated to deal with that quirk yet). Signed-off-by: Benjamin Herrenschmidt Acked-by: Bjorn Helgaas Signed-off-by: Greg Kroah-Hartman

inetdevice: fixed signed integer overflow

2014-12-06T23:05:46Z

[ Upstream commit 84bc88688e3f6ef843aa8803dbcd90168bb89faf ] There could be a signed overflow in the following code. The expression, (32-logmask) is comprised between 0 and 31 included. It may be equal to 31. In such a case the left shift will produce a signed integer overflow. According to the C99 Standard, this is an undefined behavior. A simple fix is to replace the signed int 1 with the unsigned int 1U. Signed-off-by: Vincent BENAYOUN Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

mm: memcg: handle non-error OOM situations more gracefully

2014-11-21T17:22:56Z

commit 4942642080ea82d99ab5b653abb9a12b7ba31f4a upstream. Commit 3812c8c8f395 ("mm: memcg: do not trap chargers with full callstack on OOM") assumed that only a few places that can trigger a memcg OOM situation do not return VM_FAULT_OOM, like optional page cache readahead. But there are many more and it's impractical to annotate them all. First of all, we don't want to invoke the OOM killer when the failed allocation is gracefully handled, so defer the actual kill to the end of the fault handling as well. This simplifies the code quite a bit for added bonus. Second, since a failed allocation might not be the abrupt end of the fault, the memcg OOM handler needs to be re-entrant until the fault finishes for subsequent allocation attempts. If an allocation is attempted after the task already OOMed, allow it to bypass the limit so that it can quickly finish the fault and invoke the OOM killer. Reported-by: azurIt Signed-off-by: Johannes Weiner Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Cong Wang Signed-off-by: Greg Kroah-Hartman

mm: memcg: do not trap chargers with full callstack on OOM

2014-11-21T17:22:56Z

commit 3812c8c8f3953921ef18544110dafc3505c1ac62 upstream. The memcg OOM handling is incredibly fragile and can deadlock. When a task fails to charge memory, it invokes the OOM killer and loops right there in the charge code until it succeeds. Comparably, any other task that enters the charge path at this point will go to a waitqueue right then and there and sleep until the OOM situation is resolved. The problem is that these tasks may hold filesystem locks and the mmap_sem; locks that the selected OOM victim may need to exit. For example, in one reported case, the task invoking the OOM killer was about to charge a page cache page during a write(), which holds the i_mutex. The OOM killer selected a task that was just entering truncate() and trying to acquire the i_mutex: OOM invoking task: mem_cgroup_handle_oom+0x241/0x3b0 mem_cgroup_cache_charge+0xbe/0xe0 add_to_page_cache_locked+0x4c/0x140 add_to_page_cache_lru+0x22/0x50 grab_cache_page_write_begin+0x8b/0xe0 ext3_write_begin+0x88/0x270 generic_file_buffered_write+0x116/0x290 __generic_file_aio_write+0x27c/0x480 generic_file_aio_write+0x76/0xf0 # takes ->i_mutex do_sync_write+0xea/0x130 vfs_write+0xf3/0x1f0 sys_write+0x51/0x90 system_call_fastpath+0x18/0x1d OOM kill victim: do_truncate+0x58/0xa0 # takes i_mutex do_last+0x250/0xa30 path_openat+0xd7/0x440 do_filp_open+0x49/0xa0 do_sys_open+0x106/0x240 sys_open+0x20/0x30 system_call_fastpath+0x18/0x1d The OOM handling task will retry the charge indefinitely while the OOM killed task is not releasing any resources. A similar scenario can happen when the kernel OOM killer for a memcg is disabled and a userspace task is in charge of resolving OOM situations. In this case, ALL tasks that enter the OOM path will be made to sleep on the OOM waitqueue and wait for userspace to free resources or increase the group's limit. But a userspace OOM handler is prone to deadlock itself on the locks held by the waiting tasks. For example one of the sleeping tasks may be stuck in a brk() call with the mmap_sem held for writing but the userspace handler, in order to pick an optimal victim, may need to read files from /proc/, which tries to acquire the same mmap_sem for reading and deadlocks. This patch changes the way tasks behave after detecting a memcg OOM and makes sure nobody loops or sleeps with locks held: 1. When OOMing in a user fault, invoke the OOM killer and restart the fault instead of looping on the charge attempt. This way, the OOM victim can not get stuck on locks the looping task may hold. 2. When OOMing in a user fault but somebody else is handling it (either the kernel OOM killer or a userspace handler), don't go to sleep in the charge context. Instead, remember the OOMing memcg in the task struct and then fully unwind the page fault stack with -ENOMEM. pagefault_out_of_memory() will then call back into the memcg code to check if the -ENOMEM came from the memcg, and then either put the task to sleep on the memcg's OOM waitqueue or just restart the fault. The OOM victim can no longer get stuck on any lock a sleeping task may hold. Debugged by Michal Hocko. Signed-off-by: Johannes Weiner Reported-by: azurIt Acked-by: Michal Hocko Cc: David Rientjes Cc: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Cong Wang Signed-off-by: Greg Kroah-Hartman