lwn.git/include/linux, branch docs-4.18

doc: document scope NOFS, NOIO APIs

2018-05-29T12:45:42+00:00

Although the api is documented in the source code Ted has pointed out that there is no mention in the core-api Documentation and there are people looking there to find answers how to use a specific API. Requested-by: "Theodore Y. Ts'o" Reviewed-by: Dave Chinner Signed-off-by: Michal Hocko Signed-off-by: Jonathan Corbet

Merge tag 'v4.17-rc2' into docs-next

2018-04-27T23:13:20+00:00

Merge -rc2 to pick up the changes to Documentation/core-api/kernel-api.rst that hit mainline via the networking tree. In their absence, subsequent patches cannot be applied.

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-04-22T17:49:02+00:00

Pull timer fixes from Thomas Gleixner: "A small set of timer fixes: - Evaluate the -ETIME condition correctly in the imx tpm driver - Fix the evaluation order of a condition in posix cpu timers - Use pr_cont() in the clockevents code to prevent ugly message splitting - Remove __current_kernel_time() which is now unused to prevent that new users show up. - Remove a stale forward declaration" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource/imx-tpm: Correct -ETIME return condition check posix-cpu-timers: Ensure set_process_cpu_timer is always evaluated timekeeping: Remove __current_kernel_time() timers: Remove stale struct tvec_base forward declaration clockevents: Fix kernel messages split across multiple lines

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-04-22T17:17:01+00:00

Pull perf fixes from Thomas Gleixner: "A larger set of updates for perf. Kernel: - Handle the SBOX uncore monitoring correctly on Broadwell CPUs which do not have SBOX. - Store context switch out type in PERF_RECORD_SWITCH[_CPU_WIDE]. The percentage of preempting and non-preempting context switches help understanding the nature of workloads (CPU or IO bound) that are running on a machine. This adds the kernel facility and userspace changes needed to show this information in 'perf script' and 'perf report -D' (Alexey Budankov) - Remove a WARN_ON() in the trace/kprobes code which is pointless because the return error code is already telling the caller what's wrong. - Revert a fugly workaround for clang BPF targets. - Fix sample_max_stack maximum check and do not proceed when an error has been detect, return them to avoid misidentifying errors (Jiri Olsa) - Add SPDX idenitifiers and get rid of GPL boilderplate. Tools: - Synchronize kernel ABI headers, v4.17-rc1 (Ingo Molnar) - Support MAP_FIXED_NOREPLACE, noticed when updating the tools/include/ copies (Arnaldo Carvalho de Melo) - Add '\n' at the end of parse-options error messages (Ravi Bangoria) - Add s390 support for detailed/verbose PMU event description (Thomas Richter) - perf annotate fixes and improvements: * Allow showing offsets in more than just jump targets, use the new 'O' hotkey in the TUI, config ~/.perfconfig annotate.offset_level for it and for --stdio2 (Arnaldo Carvalho de Melo) * Use the resolved variable names from objdump disassembled lines to make them more compact, just like was already done for some instructions, like "mov", this eventually will be done more generally, but lets now add some more to the existing mechanism (Arnaldo Carvalho de Melo) - perf record fixes: * Change warning for missing topology sysfs entry to debug, as not all architectures have those files, s390 being one of those (Thomas Richter) * Remove old error messages about things that unlikely to be the root cause in modern systems (Andi Kleen) - perf sched fixes: * Fix -g/--call-graph documentation (Takuya Yamamoto) - perf stat: * Enable 1ms interval for printing event counters values in (Alexey Budankov) - perf test fixes: * Run dwarf unwind on arm32 (Kim Phillips) * Remove unused ptrace.h include from LLVM test, sidesteping older clang's lack of support for some asm constructs (Arnaldo Carvalho de Melo) * Fixup BPF test using epoll_pwait syscall function probe, to cope with the syscall routines renames performed in this development cycle (Arnaldo Carvalho de Melo) - perf version fixes: * Do not print info about HAVE_LIBAUDIT_SUPPORT in 'perf version --build-options' when HAVE_SYSCALL_TABLE_SUPPORT is true, as libaudit won't be used in that case, print info about syscall_table support instead (Jin Yao) - Build system fixes: * Use HAVE_..._SUPPORT used consistently (Jin Yao) * Restore READ_ONCE() C++ compatibility in tools/include (Mark Rutland) * Give hints about package names needed to build jvmti (Arnaldo Carvalho de Melo)" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) perf/x86/intel/uncore: Fix SBOX support for Broadwell CPUs perf/x86/intel/uncore: Revert "Remove SBOX support for Broadwell server" coresight: Move to SPDX identifier perf test BPF: Fixup BPF test using epoll_pwait syscall function probe perf tests mmap: Show which tracepoint is failing perf tools: Add '\n' at the end of parse-options error messages perf record: Remove suggestion to enable APIC perf record: Remove misleading error suggestion perf hists browser: Clarify top/report browser help perf mem: Allow all record/report options perf trace: Support MAP_FIXED_NOREPLACE perf: Remove superfluous allocation error check perf: Fix sample_max_stack maximum check perf: Return proper values for user stack errors perf list: Add s390 support for detailed/verbose PMU event description perf script: Extend misc field decoding with switch out event type perf report: Extend raw dump (-D) out with switch out event type perf/core: Store context switch out type in PERF_RECORD_SWITCH[_CPU_WIDE] tools/headers: Synchronize kernel ABI headers, v4.17-rc1 trace_kprobe: Remove warning message "Could not insert probe at..." ...

kasan: add no_sanitize attribute for clang builds

2018-04-21T00:18:35+00:00

KASAN uses the __no_sanitize_address macro to disable instrumentation of particular functions. Right now it's defined only for GCC build, which causes false positives when clang is used. This patch adds a definition for clang. Note, that clang's revision 329612 or higher is required. [andreyknvl@google.com: remove redundant #ifdef CONFIG_KASAN check] Link: http://lkml.kernel.org/r/c79aa31a2a2790f6131ed607c58b0dd45dd62a6c.1523967959.git.andreyknvl@google.com Link: http://lkml.kernel.org/r/4ad725cc903f8534f8c8a60f0daade5e3d674f8d.1523554166.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Acked-by: Andrey Ryabinin Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: David Rientjes Cc: Thomas Gleixner Cc: Ingo Molnar Cc: David Woodhouse Cc: Andrey Konovalov Cc: Will Deacon Cc: Greg Kroah-Hartman Cc: Paul Lawrence Cc: Sandipan Das Cc: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

writeback: safer lock nesting

2018-04-21T00:18:35+00:00

lock_page_memcg()/unlock_page_memcg() use spin_lock_irqsave/restore() if the page's memcg is undergoing move accounting, which occurs when a process leaves its memcg for a new one that has memory.move_charge_at_immigrate set. unlocked_inode_to_wb_begin,end() use spin_lock_irq/spin_unlock_irq() if the given inode is switching writeback domains. Switches occur when enough writes are issued from a new domain. This existing pattern is thus suspicious: lock_page_memcg(page); unlocked_inode_to_wb_begin(inode, &locked); ... unlocked_inode_to_wb_end(inode, locked); unlock_page_memcg(page); If both inode switch and process memcg migration are both in-flight then unlocked_inode_to_wb_end() will unconditionally enable interrupts while still holding the lock_page_memcg() irq spinlock. This suggests the possibility of deadlock if an interrupt occurs before unlock_page_memcg(). truncate __cancel_dirty_page lock_page_memcg unlocked_inode_to_wb_begin unlocked_inode_to_wb_end end_page_writeback test_clear_page_writeback lock_page_memcg unlock_page_memcg Due to configuration limitations this deadlock is not currently possible because we don't mix cgroup writeback (a cgroupv2 feature) and memory.move_charge_at_immigrate (a cgroupv1 feature). If the kernel is hacked to always claim inode switching and memcg moving_account, then this script triggers lockup in less than a minute: cd /mnt/cgroup/memory mkdir a b echo 1 > a/memory.move_charge_at_immigrate echo 1 > b/memory.move_charge_at_immigrate ( echo $BASHPID > a/cgroup.procs while true; do dd if=/dev/zero of=/mnt/big bs=1M count=256 done ) & while true; do sync done & sleep 1h & SLEEP=$! while true; do echo $SLEEP > a/cgroup.procs echo $SLEEP > b/cgroup.procs done The deadlock does not seem possible, so it's debatable if there's any reason to modify the kernel. I suggest we should to prevent future surprises. And Wang Long said "this deadlock occurs three times in our environment", so there's more reason to apply this, even to stable. Stable 4.4 has minor conflicts applying this patch. For a clean 4.4 patch see "[PATCH for-4.4] writeback: safer lock nesting" https://lkml.org/lkml/2018/4/11/146 Wang Long said "this deadlock occurs three times in our environment" [gthelen@google.com: v4] Link: http://lkml.kernel.org/r/20180411084653.254724-1-gthelen@google.com [akpm@linux-foundation.org: comment tweaks, struct initialization simplification] Change-Id: Ibb773e8045852978f6207074491d262f1b3fb613 Link: http://lkml.kernel.org/r/20180410005908.167976-1-gthelen@google.com Fixes: 682aa8e1a6a1 ("writeback: implement unlocked_inode_to_wb transaction and use it for stat updates") Signed-off-by: Greg Thelen Reported-by: Wang Long Acked-by: Wang Long Acked-by: Michal Hocko Reviewed-by: Andrew Morton Cc: Johannes Weiner Cc: Tejun Heo Cc: Nicholas Piggin Cc: [v4.2+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fork: unconditionally clear stack on fork

2018-04-21T00:18:35+00:00

One of the classes of kernel stack content leaks[1] is exposing the contents of prior heap or stack contents when a new process stack is allocated. Normally, those stacks are not zeroed, and the old contents remain in place. In the face of stack content exposure flaws, those contents can leak to userspace. Fixing this will make the kernel no longer vulnerable to these flaws, as the stack will be wiped each time a stack is assigned to a new process. There's not a meaningful change in runtime performance; it almost looks like it provides a benefit. Performing back-to-back kernel builds before: Run times: 157.86 157.09 158.90 160.94 160.80 Mean: 159.12 Std Dev: 1.54 and after: Run times: 159.31 157.34 156.71 158.15 160.81 Mean: 158.46 Std Dev: 1.46 Instead of making this a build or runtime config, Andy Lutomirski recommended this just be enabled by default. [1] A noisy search for many kinds of stack content leaks can be seen here: https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=linux+kernel+stack+leak I did some more with perf and cycle counts on running 100,000 execs of /bin/true. before: Cycles: 218858861551 218853036130 214727610969 227656844122 224980542841 Mean: 221015379122.60 Std Dev: 4662486552.47 after: Cycles: 213868945060 213119275204 211820169456 224426673259 225489986348 Mean: 217745009865.40 Std Dev: 5935559279.99 It continues to look like it's faster, though the deviation is rather wide, but I'm not sure what I could do that would be less noisy. I'm open to ideas! Link: http://lkml.kernel.org/r/20180221021659.GA37073@beast Signed-off-by: Kees Cook Acked-by: Michal Hocko Reviewed-by: Andrew Morton Cc: Andy Lutomirski Cc: Laura Abbott Cc: Rasmus Villemoes Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2018-04-20T16:34:39+00:00

Pull networking fixes from David Miller: 1) Unbalanced refcounting in TIPC, from Jon Maloy. 2) Only allow TCP_MD5SIG to be set on sockets in close or listen state. Once the connection is established it makes no sense to change this. From Eric Dumazet. 3) Missing attribute validation in neigh_dump_table(), also from Eric Dumazet. 4) Fix address comparisons in SCTP, from Xin Long. 5) Neigh proxy table clearing can deadlock, from Wolfgang Bumiller. 6) Fix tunnel refcounting in l2tp, from Guillaume Nault. 7) Fix double list insert in team driver, from Paolo Abeni. 8) af_vsock.ko module was accidently made unremovable, from Stefan Hajnoczi. 9) Fix reference to freed llc_sap object in llc stack, from Cong Wang. 10) Don't assume netdevice struct is DMA'able memory in virtio_net driver, from Michael S. Tsirkin. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (62 commits) net/smc: fix shutdown in state SMC_LISTEN bnxt_en: Fix memory fault in bnxt_ethtool_init() virtio_net: sparse annotation fix virtio_net: fix adding vids on big-endian virtio_net: split out ctrl buffer net: hns: Avoid action name truncation docs: ip-sysctl.txt: fix name of some ipv6 variables vmxnet3: fix incorrect dereference when rxvlan is disabled llc: hold llc_sap before release_sock() MAINTAINERS: Direct networking documentation changes to netdev atm: iphase: fix spelling mistake: "Tansmit" -> "Transmit" net: qmi_wwan: add Wistron Neweb D19Q1 net: caif: fix spelling mistake "UKNOWN" -> "UNKNOWN" net: stmmac: Disable ACS Feature for GMAC >= 4 net: mvpp2: Fix DMA address mask size net: change the comment of dev_mc_init net: qualcomm: rmnet: Fix warning seen with fill_info tun: fix vlan packet truncation tipc: fix infinite loop when dumping link monitor summary tipc: fix use-after-free in tipc_nametbl_stop ...

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2018-04-20T16:15:14+00:00

Pull vfs fixes from Al Viro: "Assorted fixes. Some of that is only a matter with fault injection (broken handling of small allocation failure in various mount-related places), but the last one is a root-triggerable stack overflow, and combined with userns it gets really nasty ;-/" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: Don't leak MNT_INTERNAL away from internal mounts mm,vmscan: Allow preallocating memory for register_shrinker(). rpc_pipefs: fix double-dput() orangefs_kill_sb(): deal with allocation failures jffs2_kill_sb(): deal with failed allocations hypfs_kill_super(): deal with failed allocations

Merge tag 'for_v4.17-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

2018-04-20T16:01:26+00:00

- isofs memory leak fix - two fsnotify fixes of event mask handling - udf fix of UTF-16 handling - couple other smaller cleanups * tag 'for_v4.17-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: udf: Fix leak of UTF-16 surrogates into encoded strings fs: ext2: Adding new return type vm_fault_t isofs: fix potential memory leak in mount option parsing MAINTAINERS: add an entry for FSNOTIFY infrastructure fsnotify: fix typo in a comment about mark->g_list fsnotify: fix ignore mask logic in send_to_group() isofs compress: Remove VLA usage fs: quota: Replace GFP_ATOMIC with GFP_KERNEL in dquot_init fanotify: fix logic of events on child