kernel/linux.git/include, branch v3.18.3

mm: propagate error from stack expansion even for guard page

2015-01-16T14:59:57+00:00

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

mm: protect set_page_dirty() from ongoing truncation

2015-01-16T14:59:57+00:00

commit 2d6d7f98284648c5ed113fe22a132148950b140f upstream. Tejun, while reviewing the code, spotted the following race condition between the dirtying and truncation of a page: __set_page_dirty_nobuffers() __delete_from_page_cache() if (TestSetPageDirty(page)) page->mapping = NULL if (PageDirty()) dec_zone_page_state(page, NR_FILE_DIRTY); dec_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE); if (page->mapping) account_page_dirtied(page) __inc_zone_page_state(page, NR_FILE_DIRTY); __inc_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE); which results in an imbalance of NR_FILE_DIRTY and BDI_RECLAIMABLE. Dirtiers usually lock out truncation, either by holding the page lock directly, or in case of zap_pte_range(), by pinning the mapcount with the page table lock held. The notable exception to this rule, though, is do_wp_page(), for which this race exists. However, do_wp_page() already waits for a locked page to unlock before setting the dirty bit, in order to prevent a race where clear_page_dirty() misses the page bit in the presence of dirty ptes. Upgrade that wait to a fully locked set_page_dirty() to also cover the situation explained above. Afterwards, the code in set_page_dirty() dealing with a truncation race is no longer needed. Remove it. Reported-by: Tejun Heo Signed-off-by: Johannes Weiner Acked-by: Kirill A. Shutemov Reviewed-by: Jan Kara Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

Revert "mac80211: Fix accounting of the tailroom-needed counter"

2015-01-16T14:59:56+00:00

commit 1e359a5de861a57aa04d92bb620f52a5c1d7f8b1 upstream. This reverts commit ca34e3b5c808385b175650605faa29e71e91991b. It turns out that the p54 and cw2100 drivers assume that there's tailroom even when they don't say they really need it. However, there's currently no way for them to explicitly say they do need it, so for now revert this. This fixes https://bugzilla.kernel.org/show_bug.cgi?id=90331. Fixes: ca34e3b5c808 ("mac80211: Fix accounting of the tailroom-needed counter") Reported-by: Christopher Chavez Bisected-by: Larry Finger Debugged-by: Christian Lamparter Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman

Drivers: hv: util: make struct hv_do_fcopy match Hyper-V host messages

2015-01-16T14:59:53+00:00

commit 31d4ea1a093fcf668d5f95af44b8d41488bdb7ec upstream. An attempt to fix fcopy on i586 (bc5a5b0 Drivers: hv: util: Properly pack the data for file copy functionality) led to a regression on x86_64 (and actually didn't fix i586 breakage). Fcopy messages from Hyper-V host come in the following format: struct do_fcopy_hdr | 36 bytes 0000 | 4 bytes offset | 8 bytes size | 4 bytes data | 6144 bytes On x86_64 struct hv_do_fcopy matched this format without ' __attribute__((packed))' and on i586 adding ' __attribute__((packed))' to it doesn't change anything. Keep the structure packed and add padding to match re reality. Tested both i586 and x86_64 on Hyper-V Server 2012 R2. Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman

tracing/sched: Check preempt_count() for current when reading task->state

2015-01-16T14:59:52+00:00

commit aee4e5f3d3abb7a2239dd02f6d8fb173413fd02f upstream. When recording the state of a task for the sched_switch tracepoint a check of task_preempt_count() is performed to see if PREEMPT_ACTIVE is set. This is because, technically, a task being preempted is really in the TASK_RUNNING state, and that is what should be recorded when tracing a sched_switch, even if the task put itself into another state (it hasn't scheduled out in that state yet). But with the change to use per_cpu preempt counts, the task_thread_info(p)->preempt_count is no longer used, and instead task_preempt_count(p) is used. The problem is that this does not use the current preempt count but a stale one from a previous sched_switch. The task_preempt_count(p) uses saved_preempt_count and not preempt_count(). But for tracing sched_switch, if p is current, we really want preempt_count(). I hit this bug when I was tracing sleep and the call from do_nanosleep() scheduled out in the "RUNNING" state. sleep-4290 [000] 537272.259992: sched_switch: sleep:4290 [120] R ==> swapper/0:0 [120] sleep-4290 [000] 537272.260015: kernel_stack: => __schedule (ffffffff8150864a) => schedule (ffffffff815089f8) => do_nanosleep (ffffffff8150b76c) => hrtimer_nanosleep (ffffffff8108d66b) => SyS_nanosleep (ffffffff8108d750) => return_to_handler (ffffffff8150e8e5) => tracesys_phase2 (ffffffff8150c844) After a bit of hair pulling, I found that the state was really TASK_INTERRUPTIBLE, but the saved_preempt_count had an old PREEMPT_ACTIVE set and caused the sched_switch tracepoint to show it as RUNNING. Link: http://lkml.kernel.org/r/20141210174428.3cb7542a@gandalf.local.home Acked-by: Ingo Molnar Cc: Peter Zijlstra Fixes: 01028747559a "sched: Create more preempt_count accessors" Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

pstore-ram: Allow optional mapping with pgprot_noncached

2015-01-16T14:59:47+00:00

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

powerpc: add little endian flag to syscall_get_arch()

2015-01-16T14:59:46+00:00

commit 63f13448d81c910a284b096149411a719cbed501 upstream. Since both ppc and ppc64 have LE variants which are now reported by uname, add that flag (__AUDIT_ARCH_LE) to syscall_get_arch() and add AUDIT_ARCH_PPC64LE variant. Without this, perf trace and auditctl fail. Mainline kernel reports ppc64le (per a058801) but there is no matching AUDIT_ARCH_PPC64LE. Since 32-bit PPC LE is not supported by audit, don't advertise it in AUDIT_ARCH_PPC* variants. See: https://www.redhat.com/archives/linux-audit/2014-August/msg00082.html https://www.redhat.com/archives/linux-audit/2014-December/msg00004.html Signed-off-by: Richard Guy Briggs Acked-by: Paul Moore Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

audit: restore AUDIT_LOGINUID unset ABI

2015-01-08T18:30:27+00:00

commit 041d7b98ffe59c59fdd639931dea7d74f9aa9a59 upstream. A regression was caused by commit 780a7654cee8: audit: Make testing for a valid loginuid explicit. (which in turn attempted to fix a regression caused by e1760bd) When audit_krule_to_data() fills in the rules to get a listing, there was a missing clause to convert back from AUDIT_LOGINUID_SET to AUDIT_LOGINUID. This broke userspace by not returning the same information that was sent and expected. The rule: auditctl -a exit,never -F auid=-1 gives: auditctl -l LIST_RULES: exit,never f24=0 syscall=all when it should give: LIST_RULES: exit,never auid=-1 (0xffffffff) syscall=all Tag it so that it is reported the same way it was set. Create a new private flags audit_krule field (pflags) to store it that won't interact with the public one from the API. Signed-off-by: Richard Guy Briggs Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

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

2015-01-08T18:30:26+00:00

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

2015-01-08T18:30:25+00:00

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