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2018-10-17virtio_net: avoid using netif_tx_disable() for serializing tx routineAke Koomsin
Commit 713a98d90c5e ("virtio-net: serialize tx routine during reset") introduces netif_tx_disable() after netif_device_detach() in order to avoid use-after-free of tx queues. However, there are two issues. 1) Its operation is redundant with netif_device_detach() in case the interface is running. 2) In case of the interface is not running before suspending and resuming, the tx does not get resumed by netif_device_attach(). This results in losing network connectivity. It is better to use netif_tx_lock_bh()/netif_tx_unlock_bh() instead for serializing tx routine during reset. This also preserves the symmetry of netif_device_detach() and netif_device_attach(). Fixes commit 713a98d90c5e ("virtio-net: serialize tx routine during reset") Signed-off-by: Ake Koomsin <ake@igel.co.jp> Acked-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-18Merge tag 'trace-v4.19-rc8' of ↵Greg Kroah-Hartman
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Steven writes: "tracing: Two fixes for 4.19 This fixes two bugs: - Fix size mismatch of tracepoint array - Have preemptirq test module use same clock source of the selftest" * tag 'trace-v4.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Use trace_clock_local() for looping in preemptirq_delay_test.c tracepoint: Fix tracepoint array element size mismatch
2018-10-17udp6: fix encap return code for resubmittingPaolo Abeni
The commit eb63f2964dbe ("udp6: add missing checks on edumux packet processing") used the same return code convention of the ipv4 counterpart, but ipv6 uses the opposite one: positive values means resubmit. This change addresses the issue, using positive return value for resubmitting. Also update the related comment, which was broken, too. Fixes: eb63f2964dbe ("udp6: add missing checks on edumux packet processing") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17mlxsw: core: Fix use-after-free when flashing firmware during initIdo Schimmel
When the switch driver (e.g., mlxsw_spectrum) determines it needs to flash a new firmware version it resets the ASIC after the flashing process. The bus driver (e.g., mlxsw_pci) then registers itself again with mlxsw_core which means (among other things) that the device registers itself again with the hwmon subsystem again. Since the device was registered with the hwmon subsystem using devm_hwmon_device_register_with_groups(), then the old hwmon device (registered before the flashing) was never unregistered and was referencing stale data, resulting in a use-after free. Fix by removing reliance on device managed APIs in mlxsw_hwmon_init(). Fixes: c86d62cc410c ("mlxsw: spectrum: Reset FW after flash") Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reported-by: Alexander Petrovskiy <alexpe@mellanox.com> Tested-by: Alexander Petrovskiy <alexpe@mellanox.com> Reviewed-by: Petr Machata <petrm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17sctp: not free the new asoc when sctp_wait_for_connect returns errXin Long
When sctp_wait_for_connect is called to wait for connect ready for sp->strm_interleave in sctp_sendmsg_to_asoc, a panic could be triggered if cpu is scheduled out and the new asoc is freed elsewhere, as it will return err and later the asoc gets freed again in sctp_sendmsg. [ 285.840764] list_del corruption, ffff9f0f7b284078->next is LIST_POISON1 (dead000000000100) [ 285.843590] WARNING: CPU: 1 PID: 8861 at lib/list_debug.c:47 __list_del_entry_valid+0x50/0xa0 [ 285.846193] Kernel panic - not syncing: panic_on_warn set ... [ 285.846193] [ 285.848206] CPU: 1 PID: 8861 Comm: sctp_ndata Kdump: loaded Not tainted 4.19.0-rc7.label #584 [ 285.850559] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [ 285.852164] Call Trace: ... [ 285.872210] ? __list_del_entry_valid+0x50/0xa0 [ 285.872894] sctp_association_free+0x42/0x2d0 [sctp] [ 285.873612] sctp_sendmsg+0x5a4/0x6b0 [sctp] [ 285.874236] sock_sendmsg+0x30/0x40 [ 285.874741] ___sys_sendmsg+0x27a/0x290 [ 285.875304] ? __switch_to_asm+0x34/0x70 [ 285.875872] ? __switch_to_asm+0x40/0x70 [ 285.876438] ? ptep_set_access_flags+0x2a/0x30 [ 285.877083] ? do_wp_page+0x151/0x540 [ 285.877614] __sys_sendmsg+0x58/0xa0 [ 285.878138] do_syscall_64+0x55/0x180 [ 285.878669] entry_SYSCALL_64_after_hwframe+0x44/0xa9 This is a similar issue with the one fixed in Commit ca3af4dd28cf ("sctp: do not free asoc when it is already dead in sctp_sendmsg"). But this one can't be fixed by returning -ESRCH for the dead asoc in sctp_wait_for_connect, as it will break sctp_connect's return value to users. This patch is to simply set err to -ESRCH before it returns to sctp_sendmsg when any err is returned by sctp_wait_for_connect for sp->strm_interleave, so that no asoc would be freed due to this. When users see this error, they will know the packet hasn't been sent. And it also makes sense to not free asoc because waiting connect fails, like the second call for sctp_wait_for_connect in sctp_sendmsg_to_asoc. Fixes: 668c9beb9020 ("sctp: implement assign_number for sctp_stream_interleave") Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17sctp: fix race on sctp_id2asocMarcelo Ricardo Leitner
syzbot reported an use-after-free involving sctp_id2asoc. Dmitry Vyukov helped to root cause it and it is because of reading the asoc after it was freed: CPU 1 CPU 2 (working on socket 1) (working on socket 2) sctp_association_destroy sctp_id2asoc spin lock grab the asoc from idr spin unlock spin lock remove asoc from idr spin unlock free(asoc) if asoc->base.sk != sk ... [*] This can only be hit if trying to fetch asocs from different sockets. As we have a single IDR for all asocs, in all SCTP sockets, their id is unique on the system. An application can try to send stuff on an id that matches on another socket, and the if in [*] will protect from such usage. But it didn't consider that as that asoc may belong to another socket, it may be freed in parallel (read: under another socket lock). We fix it by moving the checks in [*] into the protected region. This fixes it because the asoc cannot be freed while the lock is held. Reported-by: syzbot+c7dd55d7aec49d48e49a@syzkaller.appspotmail.com Acked-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17r8169: re-enable MSI-X on RTL8168gHeiner Kallweit
Similar to d49c88d7677b ("r8169: Enable MSI-X on RTL8106e") after e9d0ba506ea8 ("PCI: Reprogram bridge prefetch registers on resume") we can safely assume that this also fixes the root cause of the issue worked around by 7c53a722459c ("r8169: don't use MSI-X on RTL8168g"). So let's revert it. Fixes: 7c53a722459c ("r8169: don't use MSI-X on RTL8168g") Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17net: bpfilter: use get_pid_task instead of pid_taskTaehee Yoo
pid_task() dereferences rcu protected tasks array. But there is no rcu_read_lock() in shutdown_umh() routine so that rcu_read_lock() is needed. get_pid_task() is wrapper function of pid_task. it holds rcu_read_lock() then calls pid_task(). if task isn't NULL, it increases reference count of task. test commands: %modprobe bpfilter %modprobe -rv bpfilter splat looks like: [15102.030932] ============================= [15102.030957] WARNING: suspicious RCU usage [15102.030985] 4.19.0-rc7+ #21 Not tainted [15102.031010] ----------------------------- [15102.031038] kernel/pid.c:330 suspicious rcu_dereference_check() usage! [15102.031063] other info that might help us debug this: [15102.031332] rcu_scheduler_active = 2, debug_locks = 1 [15102.031363] 1 lock held by modprobe/1570: [15102.031389] #0: 00000000580ef2b0 (bpfilter_lock){+.+.}, at: stop_umh+0x13/0x52 [bpfilter] [15102.031552] stack backtrace: [15102.031583] CPU: 1 PID: 1570 Comm: modprobe Not tainted 4.19.0-rc7+ #21 [15102.031607] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 07/08/2015 [15102.031628] Call Trace: [15102.031676] dump_stack+0xc9/0x16b [15102.031723] ? show_regs_print_info+0x5/0x5 [15102.031801] ? lockdep_rcu_suspicious+0x117/0x160 [15102.031855] pid_task+0x134/0x160 [15102.031900] ? find_vpid+0xf0/0xf0 [15102.032017] shutdown_umh.constprop.1+0x1e/0x53 [bpfilter] [15102.032055] stop_umh+0x46/0x52 [bpfilter] [15102.032092] __x64_sys_delete_module+0x47e/0x570 [ ... ] Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17ptp: fix Spectre v1 vulnerabilityGustavo A. R. Silva
pin_index can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/ptp/ptp_chardev.c:253 ptp_ioctl() warn: potential spectre issue 'ops->pin_config' [r] (local cap) Fix this by sanitizing pin_index before using it to index ops->pin_config, and before passing it as an argument to function ptp_set_pinfunc(), in which it is used to index info->pin_config. Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17sparc: vDSO: Silence an uninitialized variable warningDan Carpenter
Smatch complains that "val" would be uninitialized if kstrtoul() fails. Fixes: 9a08862a5d2e ("vDSO for sparc") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17net: qla3xxx: Remove overflowing shift statementNathan Chancellor
Clang currently warns: drivers/net/ethernet/qlogic/qla3xxx.c:384:24: warning: signed shift result (0xF00000000) requires 37 bits to represent, but 'int' only has 32 bits [-Wshift-overflow] ((ISP_NVRAM_MASK << 16) | qdev->eeprom_cmd_data)); ~~~~~~~~~~~~~~ ^ ~~ 1 warning generated. The warning is certainly accurate since ISP_NVRAM_MASK is defined as (0x000F << 16) which is then shifted by 16, resulting in 64424509440, well above UINT_MAX. Given that this is the only location in this driver where ISP_NVRAM_MASK is shifted again, it seems likely that ISP_NVRAM_MASK was originally defined without a shift and during the move of the shift to the definition, this statement wasn't properly removed (since ISP_NVRAM_MASK is used in the statenent right above this). Only the maintainers can confirm this since this statment has been here since the driver was first added to the kernel. Link: https://github.com/ClangBuiltLinux/linux/issues/127 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17Merge branch 'geneve-vxlan-mtu'David S. Miller
Stefano Brivio says: ==================== geneve, vxlan: Don't set exceptions if skb->len < mtu This series fixes the exception abuse described in 2/2, and 1/2 is just a preparatory change to make 2/2 less ugly. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17geneve, vxlan: Don't set exceptions if skb->len < mtuStefano Brivio
We shouldn't abuse exceptions: if the destination MTU is already higher than what we're transmitting, no exception should be created. Fixes: 52a589d51f10 ("geneve: update skb dst pmtu on tx path") Fixes: a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path") Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17geneve, vxlan: Don't check skb_dst() twiceStefano Brivio
Commit f15ca723c1eb ("net: don't call update_pmtu unconditionally") avoids that we try updating PMTU for a non-existent destination, but didn't clean up cases where the check was already explicit. Drop those redundant checks. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17sparc: Fix syscall fallback bugs in VDSO.David S. Miller
First, the trap number for 32-bit syscalls is 0x10. Also, only negate the return value when syscall error is indicated by the carry bit being set. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-18x86/mcelog: Remove one mce_helper definitionSebastian Andrzej Siewior
Commit 5de97c9f6d85f ("x86/mce: Factor out and deprecate the /dev/mcelog driver") moved the old interface into one file including mce_helper definition as static and "extern". Remove one. Fixes: 5de97c9f6d85f ("x86/mce: Factor out and deprecate the /dev/mcelog driver") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> CC: "H. Peter Anvin" <hpa@zytor.com> CC: Ingo Molnar <mingo@redhat.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Tony Luck <tony.luck@intel.com> CC: linux-edac <linux-edac@vger.kernel.org> CC: x86-ml <x86@kernel.org> Link: http://lkml.kernel.org/r/20181017170554.18841-3-bigeasy@linutronix.de
2018-10-17tracing: Use trace_clock_local() for looping in preemptirq_delay_test.cSteven Rostedt (VMware)
The preemptirq_delay_test module is used for the ftrace selftest code that tests the latency tracers. The problem is that it uses ktime for the delay loop, and then checks the tracer to see if the delay loop is caught, but the tracer uses trace_clock_local() which uses various different other clocks to measure the latency. As ktime uses the clock cycles, and the code then converts that to nanoseconds, it causes rounding errors, and the preemptirq latency tests are failing due to being off by 1 (it expects to see a delay of 500000 us, but the delay is only 499999 us). This is happening due to a rounding error in the ktime (which is totally legit). The purpose of the test is to see if it can catch the delay, not to test the accuracy between trace_clock_local() and ktime_get(). Best to use apples to apples, and have the delay loop use the same clock as the latency tracer does. Cc: stable@vger.kernel.org Fixes: f96e8577da102 ("lib: Add module for testing preemptoff/irqsoff latency tracers") Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-10-17tracepoint: Fix tracepoint array element size mismatchMathieu Desnoyers
commit 46e0c9be206f ("kernel: tracepoints: add support for relative references") changes the layout of the __tracepoint_ptrs section on architectures supporting relative references. However, it does so without turning struct tracepoint * const into const int elsewhere in the tracepoint code, which has the following side-effect: Setting mod->num_tracepoints is done in by module.c: mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs", sizeof(*mod->tracepoints_ptrs), &mod->num_tracepoints); Basically, since sizeof(*mod->tracepoints_ptrs) is a pointer size (rather than sizeof(int)), num_tracepoints is erroneously set to half the size it should be on 64-bit arch. So a module with an odd number of tracepoints misses the last tracepoint due to effect of integer division. So in the module going notifier: for_each_tracepoint_range(mod->tracepoints_ptrs, mod->tracepoints_ptrs + mod->num_tracepoints, tp_module_going_check_quiescent, NULL); the expression (mod->tracepoints_ptrs + mod->num_tracepoints) actually evaluates to something within the bounds of the array, but miss the last tracepoint if the number of tracepoints is odd on 64-bit arch. Fix this by introducing a new typedef: tracepoint_ptr_t, which is either "const int" on architectures that have PREL32 relocations, or "struct tracepoint * const" on architectures that does not have this feature. Also provide a new tracepoint_ptr_defer() static inline to encapsulate deferencing this type rather than duplicate code and ugly idefs within the for_each_tracepoint_range() implementation. This issue appears in 4.19-rc kernels, and should ideally be fixed before the end of the rc cycle. Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Jessica Yu <jeyu@kernel.org> Link: http://lkml.kernel.org/r/20181013191050.22389-1-mathieu.desnoyers@efficios.com Link: http://lkml.kernel.org/r/20180704083651.24360-7-ard.biesheuvel@linaro.org Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morris <james.morris@microsoft.com> Cc: James Morris <jmorris@namei.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Nicolas Pitre <nico@linaro.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Russell King <linux@armlinux.org.uk> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-10-17spi: sh-msiof: document R8A779{7|8}0 bindingsSergei Shtylyov
Document the R-Car V3{M|H} (R8A779{7|8}0) SoCs in the Renesas MSIOF bindings. Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> Reviewed-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Mark Brown <broonie@kernel.org>
2018-10-17usb: gadget: storage: Fix Spectre v1 vulnerabilityGustavo A. R. Silva
num can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/usb/gadget/function/f_mass_storage.c:3177 fsg_lun_make() warn: potential spectre issue 'fsg_opts->common->luns' [r] (local cap) Fix this by sanitizing num before using it to index fsg_opts->common->luns Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Acked-by: Felipe Balbi <felipe.balbi@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-17perf tools: Stop fallbacking to kallsyms for vdso symbols lookupArnaldo Carvalho de Melo
David reports that: <quote> Perf has this hack where it uses the kernel symbol map as a backup when a symbol can't be found in the user's symbol table(s). This causes problems because the tests driving this code path use machine__kernel_ip(), and that is completely meaningless on Sparc. On sparc64 the kernel and user live in physically separate virtual address spaces, rather than a shared one. And the kernel lives at a virtual address that overlaps common userspace addresses. So this test passes almost all the time when a user symbol lookup fails. The consequence of this is that, if the unfound user virtual address in the sample doesn't match up to a kernel symbol either, we trigger things like this code in builtin-top.c: if (al.sym == NULL && al.map != NULL) { const char *msg = "Kernel samples will not be resolved.\n"; /* * As we do lazy loading of symtabs we only will know if the * specified vmlinux file is invalid when we actually have a * hit in kernel space and then try to load it. So if we get * here and there are _no_ symbols in the DSO backing the * kernel map, bail out. * * We may never get here, for instance, if we use -K/ * --hide-kernel-symbols, even if the user specifies an * invalid --vmlinux ;-) */ if (!machine->kptr_restrict_warned && !top->vmlinux_warned && __map__is_kernel(al.map) && map__has_symbols(al.map)) { if (symbol_conf.vmlinux_name) { char serr[256]; dso__strerror_load(al.map->dso, serr, sizeof(serr)); ui__warning("The %s file can't be used: %s\n%s", symbol_conf.vmlinux_name, serr, msg); } else { ui__warning("A vmlinux file was not found.\n%s", msg); } if (use_browser <= 0) sleep(5); top->vmlinux_warned = true; } } When I fire up a compilation on sparc, this triggers immediately. I'm trying to figure out what the "backup to kernel map" code is accomplishing. I see some language in the current code and in the changes that have happened in this area talking about vdso. Does that really happen? The vdso is mapped into userspace virtual addresses, not kernel ones. More history. This didn't cause problems on sparc some time ago, because the kernel IP check used to be "ip < 0" :-) Sparc kernel addresses are not negative. But now with machine__kernel_ip(), which works using the symbol table determined kernel address range, it does trigger. What it all boils down to is that on architectures like sparc, machine__kernel_ip() should always return false in this scenerio, and therefore this kind of logic: if (cpumode == PERF_RECORD_MISC_USER && machine && mg != &machine->kmaps && machine__kernel_ip(machine, al->addr)) { is basically invalid. PERF_RECORD_MISC_USER implies no kernel address can possibly match for the sample/event in question (no matter how hard you try!) :-) </> So, I thought something had changed and in the past we would somehow find that address in the kallsyms, but I couldn't find anything to back that up, the patch introducing this is over a decade old, lots of things changed, so I was just thinking I was missing something. I tried a gtod busy loop to generate vdso activity and added a 'perf probe' at that branch, on x86_64 to see if it ever gets hit: Made thread__find_map() noinline, as 'perf probe' in lines of inline functions seems to not be working, only at function start. (Masami?) # perf probe -x ~/bin/perf -L thread__find_map:57 <thread__find_map@/home/acme/git/perf/tools/perf/util/event.c:57> 57 if (cpumode == PERF_RECORD_MISC_USER && machine && 58 mg != &machine->kmaps && 59 machine__kernel_ip(machine, al->addr)) { 60 mg = &machine->kmaps; 61 load_map = true; 62 goto try_again; } } else { /* * Kernel maps might be changed when loading * symbols so loading * must be done prior to using kernel maps. */ 69 if (load_map) 70 map__load(al->map); 71 al->addr = al->map->map_ip(al->map, al->addr); # perf probe -x ~/bin/perf thread__find_map:60 Added new event: probe_perf:thread__find_map (on thread__find_map:60 in /home/acme/bin/perf) You can now use it in all perf tools, such as: perf record -e probe_perf:thread__find_map -aR sleep 1 # Then used this to see if, system wide, those probe points were being hit: # perf trace -e *perf:thread*/max-stack=8/ ^C[root@jouet ~]# No hits when running 'perf top' and: # cat gtod.c #include <sys/time.h> int main(void) { struct timeval tv; while (1) gettimeofday(&tv, 0); return 0; } [root@jouet c]# ./gtod ^C Pressed 'P' in 'perf top' and the [vdso] samples are there: 62.84% [vdso] [.] __vdso_gettimeofday 8.13% gtod [.] main 7.51% [vdso] [.] 0x0000000000000914 5.78% [vdso] [.] 0x0000000000000917 5.43% gtod [.] _init 2.71% [vdso] [.] 0x000000000000092d 0.35% [kernel] [k] native_io_delay 0.33% libc-2.26.so [.] __memmove_avx_unaligned_erms 0.20% [vdso] [.] 0x000000000000091d 0.17% [i2c_i801] [k] i801_access 0.06% firefox [.] free 0.06% libglib-2.0.so.0.5400.3 [.] g_source_iter_next 0.05% [vdso] [.] 0x0000000000000919 0.05% libpthread-2.26.so [.] __pthread_mutex_lock 0.05% libpixman-1.so.0.34.0 [.] 0x000000000006d3a7 0.04% [kernel] [k] entry_SYSCALL_64_trampoline 0.04% libxul.so [.] style::dom_apis::query_selector_slow 0.04% [kernel] [k] module_get_kallsym 0.04% firefox [.] malloc 0.04% [vdso] [.] 0x0000000000000910 I added a 'perf probe' to thread__find_map:69, and that surely got tons of hits, i.e. for every map found, just to make sure the 'perf probe' command was really working. In the process I noticed a bug, we're only have records for '[vdso]' for pre-existing commands, i.e. ones that are running when we start 'perf top', when we will generate the PERF_RECORD_MMAP by looking at /perf/PID/maps. I.e. like this, for preexisting processes with a vdso map, again, tracing for all the system, only pre-existing processes get a [vdso] map (when having one): [root@jouet ~]# perf probe -x ~/bin/perf __machine__addnew_vdso Added new event: probe_perf:__machine__addnew_vdso (on __machine__addnew_vdso in /home/acme/bin/perf) You can now use it in all perf tools, such as: perf record -e probe_perf:__machine__addnew_vdso -aR sleep 1 [root@jouet ~]# perf trace -e probe_perf:__machine__addnew_vdso/max-stack=8/ 0.000 probe_perf:__machine__addnew_vdso:(568eb3) __machine__addnew_vdso (/home/acme/bin/perf) map__new (/home/acme/bin/perf) machine__process_mmap2_event (/home/acme/bin/perf) machine__process_event (/home/acme/bin/perf) perf_event__process (/home/acme/bin/perf) perf_tool__process_synth_event (/home/acme/bin/perf) perf_event__synthesize_mmap_events (/home/acme/bin/perf) __event__synthesize_thread (/home/acme/bin/perf) The kernel is generating a PERF_RECORD_MMAP for vDSOs, but somehow 'perf top' is not getting those records while 'perf record' is: # perf record ~acme/c/gtod ^C[ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.076 MB perf.data (1499 samples) ] # perf report -D | grep PERF_RECORD_MMAP2 71293612401913 0x11b48 [0x70]: PERF_RECORD_MMAP2 25484/25484: [0x400000(0x1000) @ 0 fd:02 1137 541179306]: r-xp /home/acme/c/gtod 71293612419012 0x11be0 [0x70]: PERF_RECORD_MMAP2 25484/25484: [0x7fa4a2783000(0x227000) @ 0 fd:00 3146370 854107250]: r-xp /usr/lib64/ld-2.26.so 71293612432110 0x11c50 [0x60]: PERF_RECORD_MMAP2 25484/25484: [0x7ffcdb53a000(0x2000) @ 0 00:00 0 0]: r-xp [vdso] 71293612509944 0x11cb0 [0x70]: PERF_RECORD_MMAP2 25484/25484: [0x7fa4a23cd000(0x3b6000) @ 0 fd:00 3149723 262067164]: r-xp /usr/lib64/libc-2.26.so # # perf script | grep vdso | head gtod 25484 71293.612768: 2485554 cycles:ppp: 7ffcdb53a914 [unknown] ([vdso]) gtod 25484 71293.613576: 2149343 cycles:ppp: 7ffcdb53a917 [unknown] ([vdso]) gtod 25484 71293.614274: 1814652 cycles:ppp: 7ffcdb53aca8 __vdso_gettimeofday+0x98 ([vdso]) gtod 25484 71293.614862: 1669070 cycles:ppp: 7ffcdb53acc5 __vdso_gettimeofday+0xb5 ([vdso]) gtod 25484 71293.615404: 1451589 cycles:ppp: 7ffcdb53acc5 __vdso_gettimeofday+0xb5 ([vdso]) gtod 25484 71293.615999: 1269941 cycles:ppp: 7ffcdb53ace6 __vdso_gettimeofday+0xd6 ([vdso]) gtod 25484 71293.616405: 1177946 cycles:ppp: 7ffcdb53a914 [unknown] ([vdso]) gtod 25484 71293.616775: 1121290 cycles:ppp: 7ffcdb53ac47 __vdso_gettimeofday+0x37 ([vdso]) gtod 25484 71293.617150: 1037721 cycles:ppp: 7ffcdb53ace6 __vdso_gettimeofday+0xd6 ([vdso]) gtod 25484 71293.617478: 994526 cycles:ppp: 7ffcdb53ace6 __vdso_gettimeofday+0xd6 ([vdso]) # The patch is the obvious one and with it we also continue to resolve vdso symbols for pre-existing processes in 'perf top' and for all processes in 'perf record' + 'perf report/script'. Suggested-by: David Miller <davem@davemloft.net> Acked-by: David Miller <davem@davemloft.net> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: https://lkml.kernel.org/n/tip-cs7skq9pp0kjypiju6o7trse@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-10-17Merge branch 'nvme-4.19' of git://git.infradead.org/nvme into for-linusJens Axboe
Pull single NVMe fix from Christoph. * 'nvme-4.19' of git://git.infradead.org/nvme: nvme: remove ns sibling before clearing path
2018-10-17drivers/block: Remove DAC960 driverHannes Reinecke
The DAC960 driver has been obsoleted by the myrb/myrs drivers, so it can be dropped. Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-17Merge branch 'parisc-4.19-3' of ↵Greg Kroah-Hartman
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux Helge writes: "parisc fix: Fix an unitialized variable usage in the parisc unwind code." * 'parisc-4.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: Fix uninitialized variable usage in unwind.c
2018-10-17Merge tag 'clk-fixes-for-linus' of ↵Greg Kroah-Hartman
git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux Stephen writes: "clk fixes for v4.19-rc8 One fix for the Allwinner A10 SoC's audio PLL that wasn't properly set and generating noise." * tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: clk: sunxi-ng: sun4i: Set VCO and PLL bias current to lowest setting
2018-10-17x86/fpu: Fix i486 + no387 boot crash by only saving FPU registers on context ↵Sebastian Andrzej Siewior
switch if there is an FPU Booting an i486 with "no387 nofxsr" ends with with the following crash: math_emulate: 0060:c101987d Kernel panic - not syncing: Math emulation needed in kernel on the first context switch in user land. The reason is that copy_fpregs_to_fpstate() tries FNSAVE which does not work as the FPU is turned off. This bug was introduced in: f1c8cd0176078 ("x86/fpu: Change fpu->fpregs_active users to fpu->fpstate_active") Add a check for X86_FEATURE_FPU before trying to save FPU registers (we have such a check in switch_fpu_finish() already). Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: f1c8cd0176078 ("x86/fpu: Change fpu->fpregs_active users to fpu->fpstate_active") Link: http://lkml.kernel.org/r/20181016202525.29437-4-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-10-17x86/fpu: Remove second definition of fpu in __fpu__restore_sig()Sebastian Andrzej Siewior
Commit: c5bedc6847c3b ("x86/fpu: Get rid of PF_USED_MATH usage, convert it to fpu->fpstate_active") introduced the 'fpu' variable at top of __restore_xstate_sig(), which now shadows the other definition: arch/x86/kernel/fpu/signal.c:318:28: warning: symbol 'fpu' shadows an earlier one arch/x86/kernel/fpu/signal.c:271:20: originally declared here Remove the shadowed definition of 'fpu', as the two definitions are the same. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: c5bedc6847c3b ("x86/fpu: Get rid of PF_USED_MATH usage, convert it to fpu->fpstate_active") Link: http://lkml.kernel.org/r/20181016202525.29437-3-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-10-17x86/entry/64: Further improve paranoid_entry commentsAndy Lutomirski
Commit: 16561f27f94e ("x86/entry: Add some paranoid entry/exit CR3 handling comments") ... added some comments. This improves them a bit: - When I first read the new comments, it was unclear to me whether they were referring to the case where paranoid_entry interrupted other entry code or where paranoid_entry was itself interrupted. Clarify it. - Remove the EBX comment. We no longer use EBX as a SWAPGS indicator. Signed-off-by: Andy Lutomirski <luto@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/c47daa1888dc2298e7e1d3f82bd76b776ea33393.1539542111.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-10-17x86/entry/32: Clear the CS high bitsJan Kiszka
Even if not on an entry stack, the CS's high bits must be initialized because they are unconditionally evaluated in PARANOID_EXIT_TO_KERNEL_MODE. Failing to do so broke the boot on Galileo Gen2 and IOT2000 boards. [ bp: Make the commit message tone passive and impartial. ] Fixes: b92a165df17e ("x86/entry/32: Handle Entry from Kernel-Mode on Entry-Stack") Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Joerg Roedel <jroedel@suse.de> Acked-by: Joerg Roedel <jroedel@suse.de> CC: "H. Peter Anvin" <hpa@zytor.com> CC: Andrea Arcangeli <aarcange@redhat.com> CC: Andy Lutomirski <luto@kernel.org> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: Brian Gerst <brgerst@gmail.com> CC: Dave Hansen <dave.hansen@intel.com> CC: David Laight <David.Laight@aculab.com> CC: Denys Vlasenko <dvlasenk@redhat.com> CC: Eduardo Valentin <eduval@amazon.com> CC: Greg KH <gregkh@linuxfoundation.org> CC: Ingo Molnar <mingo@kernel.org> CC: Jiri Kosina <jkosina@suse.cz> CC: Josh Poimboeuf <jpoimboe@redhat.com> CC: Juergen Gross <jgross@suse.com> CC: Linus Torvalds <torvalds@linux-foundation.org> CC: Peter Zijlstra <peterz@infradead.org> CC: Thomas Gleixner <tglx@linutronix.de> CC: Will Deacon <will.deacon@arm.com> CC: aliguori@amazon.com CC: daniel.gruss@iaik.tugraz.at CC: hughd@google.com CC: keescook@google.com CC: linux-mm <linux-mm@kvack.org> CC: x86-ml <x86@kernel.org> Link: http://lkml.kernel.org/r/f271c747-1714-5a5b-a71f-ae189a093b8d@siemens.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-10-17spi: pic32-sqi: don't pass GFP_DMA32 to dma_alloc_coherentChristoph Hellwig
The DMA API does its own zone decisions based on the coherent_dma_mask. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2018-10-17cpufreq: tegra186: don't pass GFP_DMA32 to dma_alloc_coherent()Christoph Hellwig
The DMA API does its own zone decisions based on the coherent_dma_mask. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-10-17nvme-pci: fix hot removal during error handlingKeith Busch
A removal waits for the reset_work to complete. If a surprise removal occurs around the same time as an error triggered controller reset, and reset work happened to dispatch a command to the removed controller, the command won't be recovered since the timeout work doesn't do anything during error recovery. We wouldn't want to wait for timeout handling anyway, so this patch fixes this by disabling the controller and killing admin queues prior to syncing with the reset_work. Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvmet-fcloop: suppress a compiler warningBart Van Assche
Building with W=1 enables the compiler warning -Wimplicit-fallthrough=3. That option does not recognize the fall-through comment in the fcloop driver. Add a fall-through comment that is recognized for -Wimplicit-fallthrough=3. This patch avoids that the compiler reports the following warning when building with W=1: drivers/nvme/target/fcloop.c:647:6: warning: this statement may fall through [-Wimplicit-fallthrough=] if (op == NVMET_FCOP_READDATA) ^ Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvme-core: make implicit seed truncation explicitBart Van Assche
The nvme_user_io.slba field is 64 bits wide. That value is copied into the 32-bit bio_integrity_payload.bip_iter.bi_sector field. Make that truncation explicit to avoid that Coverity complains about implicit truncation. See also Coverity ID 1056486 on http://scan.coverity.com/projects/linux. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvmet-fc: fix kernel-doc headersBart Van Assche
This patch avoids that the kernel-doc tool complains about two function headers when building with W=1. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvme-fc: rework the request initialization codeBart Van Assche
Instead of setting and then clearing the first_sgl pointer for AEN requests, leave that pointer zero. This patch does not change how requests are initialized but avoids that Coverity reports the following complaint for nvme_fc_init_aen_ops(): CID 1418400 (#1 of 1): Out-of-bounds access (OVERRUN) 4. overrun-buffer-val: Overrunning buffer pointed to by aen_op of 312 bytes by passing it to a function which accesses it at byte offset 312. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvme-fc: introduce struct nvme_fcp_op_w_sglBart Van Assche
This patch does not change any functionality but makes the intent of the code more clear. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvme-fc: fix kernel-doc headersBart Van Assche
This patch avoids that the kernel-doc tool complains about several multiple function headers when building with W=1. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvmet: avoid integer overflow in the discard codeBart Van Assche
Although I'm not sure whether it is a good idea to support large discard commands, I think integer overflow for discard ranges larger than 4 GB should be avoided. This patch avoids that smatch reports the following: drivers/nvme/target/io-cmd-file.c:249:1 nvmet_file_execute_discard() warn: should '((range.nlb)) << req->ns->blksize_shift' be a 64 bit type? Fixes: d5eff33ee6f8 ("nvmet: add simple file backed ns support") Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvmet-rdma: declare local symbols staticBart Van Assche
This patch avoids that sparse complains about missing declarations. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvmet: use strlcpy() instead of strcpy()Bart Van Assche
Although the code modified by this patch looks fine to me, this patch avoids that Coverity reports the following complaint (ID 1364971 and ID 1364973): "You might overrun the 256-character fixed-size string id->subnqn". Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvme-pci: fix nvme_suspend_queue() kernel-doc headerBart Van Assche
This patch avoids that the kernel-doc tool complains about the nvme_suspend_queue() function header when building with W=1. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvme-core: rework a NQN copying operationBart Van Assche
Although it is easy to see that the code in nvme_init_subnqn() guarantees that the subsys->nqn string is '\0'-terminated, apparently Coverity is not smart enough to see this. Make it easier for Coverity to analyze this code by changing the strncpy() call into a strlcpy() call. This patch does not change the behavior of the code but fixes Coveritiy ID 1423720. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvme-core: declare local symbols staticBart Van Assche
This patch avoids that sparse complains about missing declarations. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvmet-rdma: check for timeout in nvme_rdma_wait_for_cm()Bart Van Assche
Check whether queue->cm_error holds a value before reading it. This patch addresses Coverity ID 1373774: unchecked return value. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvmet: use strcmp() instead of strncmp() for subsystem lookupBart Van Assche
strncmp() stops comparing when either the end of one of the first two arguments is reached or when 'n' characters have been compared, whichever comes first. That means that strncmp(s1, s2, n) is equivalent to strcmp(s1, s2) if n exceeds the length of s1 or the length of s2. Since that is the case in nvmet_find_get_subsys(), change strncmp() into strcmp(). This patch avoids that the following warning is reported by smatch: drivers/nvme/target/core.c:940:1 nvmet_find_get_subsys() error: strncmp() '"nqn.2014-08.org.nvmexpress.discovery"' too small (37 vs 223) Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvmet: remove unreachable codeChaitanya Kulkarni
Get rid of the unreachable code in the nvmet_parse_discovery_cmd(). Keep the error message identical to the admin-cmd.c and io-cmd*.c Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17nvme: update node paths after adding new pathKeith Busch
The nvme namespace paths were being updated only when the current path was not set or nonoptimized. If a new path comes online that is a better path for its NUMA node, the multipath selector may continue using the previously set path on a potentially further node. This patch re-runs the path assignment after successfully adding a new optimized path. Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-17x86/kconfig: Remove redundant 'default n' lines from all x86 Kconfig'sBartlomiej Zolnierkiewicz
'default n' is the default value for any bool or tristate Kconfig setting so there is no need to write it explicitly. Also, since commit: f467c5640c29 ("kconfig: only write '# CONFIG_FOO is not set' for visible symbols") ... the Kconfig behavior is the same regardless of 'default n' being present or not: ... One side effect of (and the main motivation for) this change is making the following two definitions behave exactly the same: config FOO bool config FOO bool default n With this change, neither of these will generate a '# CONFIG_FOO is not set' line (assuming FOO isn't selected/implied). That might make it clearer to people that a bare 'default n' is redundant. ... Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Juergen Gross <jgross@suse.co> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20181016134217eucas1p2102984488b89178a865162553369025b%7EeGpI5NlJo0851008510eucas1p2D@eucas1p2.samsung.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-10-17locking/pvqspinlock: Extend node size when pvqspinlock is configuredWaiman Long
The qspinlock code supports up to 4 levels of slowpath nesting using four per-CPU mcs_spinlock structures. For 64-bit architectures, they fit nicely in one 64-byte cacheline. For para-virtualized (PV) qspinlocks it needs to store more information in the per-CPU node structure than there is space for. It uses a trick to use a second cacheline to hold the extra information that it needs. So PV qspinlock needs to access two extra cachelines for its information whereas the native qspinlock code only needs one extra cacheline. Freshly added counter profiling of the qspinlock code, however, revealed that it was very rare to use more than two levels of slowpath nesting. So it doesn't make sense to penalize PV qspinlock code in order to have four mcs_spinlock structures in the same cacheline to optimize for a case in the native qspinlock code that rarely happens. Extend the per-CPU node structure to have two more long words when PV qspinlock locks are configured to hold the extra data that it needs. As a result, the PV qspinlock code will enjoy the same benefit of using just one extra cacheline like the native counterpart, for most cases. [ mingo: Minor changelog edits. ] Signed-off-by: Waiman Long <longman@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1539697507-28084-2-git-send-email-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>