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2020-01-14alarmtimer: Provide get_timespec() callbackAndrei Vagin
The upcoming support for time namespaces requires to have access to: - The time in a task's time namespace for sys_clock_gettime() - The time in the root name space for common_timer_get() Wire up alarm bases with get_timespec(). Suggested-by: Thomas Gleixner <tglx@linutronix.de> Co-developed-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191112012724.250792-9-dima@arista.com
2020-01-14alarmtimer: Rename gettime() callback to get_ktime()Andrei Vagin
The upcoming support for time namespaces requires to have access to: - The time in a tasks time namespace for sys_clock_gettime() - The time in the root name space for common_timer_get() struct alarm_base needs to follow the same naming convention, so rename .gettime() callback into get_ktime() as a preparation for introducing get_timespec(). Suggested-by: Thomas Gleixner <tglx@linutronix.de> Co-developed-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191112012724.250792-8-dima@arista.com
2020-01-14posix-clocks: Rename .clock_get_timespec() callbacks accordinglyAndrei Vagin
The upcoming support for time namespaces requires to have access to: - The time in a task's time namespace for sys_clock_gettime() - The time in the root name space for common_timer_get() That adds a valid reason to finally implement a separate callback which returns the time in ktime_t format in (struct k_clock). As a preparation ground for introducing clock_get_ktime(), the original callback clock_get() was renamed into clock_get_timespec(). Reflect the renaming into the callback implementations. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Co-developed-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191112012724.250792-7-dima@arista.com
2020-01-14posix-clocks: Rename the clock_get() callback to clock_get_timespec()Andrei Vagin
The upcoming support for time namespaces requires to have access to: - The time in a task's time namespace for sys_clock_gettime() - The time in the root name space for common_timer_get() That adds a valid reason to finally implement a separate callback which returns the time in ktime_t format, rather than in (struct timespec). Rename the clock_get() callback to clock_get_timespec() as a preparation for introducing clock_get_ktime(). Suggested-by: Thomas Gleixner <tglx@linutronix.de> Co-developed-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191112012724.250792-6-dima@arista.com
2020-01-14time: Add timens_offsets to be used for tasks in time namespaceAndrei Vagin
Introduce offsets for time namespace. They will contain an adjustment needed to convert clocks to/from host's. A new namespace is created with the same offsets as the time namespace of the current process. Co-developed-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrei Vagin <avagin@openvz.org> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191112012724.250792-5-dima@arista.com
2020-01-14ns: Introduce Time NamespaceAndrei Vagin
Time Namespace isolates clock values. The kernel provides access to several clocks CLOCK_REALTIME, CLOCK_MONOTONIC, CLOCK_BOOTTIME, etc. CLOCK_REALTIME System-wide clock that measures real (i.e., wall-clock) time. CLOCK_MONOTONIC Clock that cannot be set and represents monotonic time since some unspecified starting point. CLOCK_BOOTTIME Identical to CLOCK_MONOTONIC, except it also includes any time that the system is suspended. For many users, the time namespace means the ability to changes date and time in a container (CLOCK_REALTIME). Providing per namespace notions of CLOCK_REALTIME would be complex with a massive overhead, but has a dubious value. But in the context of checkpoint/restore functionality, monotonic and boottime clocks become interesting. Both clocks are monotonic with unspecified starting points. These clocks are widely used to measure time slices and set timers. After restoring or migrating processes, it has to be guaranteed that they never go backward. In an ideal case, the behavior of these clocks should be the same as for a case when a whole system is suspended. All this means that it is required to set CLOCK_MONOTONIC and CLOCK_BOOTTIME clocks, which can be achieved by adding per-namespace offsets for clocks. A time namespace is similar to a pid namespace in the way how it is created: unshare(CLONE_NEWTIME) system call creates a new time namespace, but doesn't set it to the current process. Then all children of the process will be born in the new time namespace, or a process can use the setns() system call to join a namespace. This scheme allows setting clock offsets for a namespace, before any processes appear in it. All available clone flags have been used, so CLONE_NEWTIME uses the highest bit of CSIGNAL. It means that it can be used only with the unshare() and the clone3() system calls. [ tglx: Adjusted paragraph about clone3() to reality and massaged the changelog a bit. ] Co-developed-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://criu.org/Time_namespace Link: https://lists.openvz.org/pipermail/criu/2018-June/041504.html Link: https://lore.kernel.org/r/20191112012724.250792-4-dima@arista.com
2020-01-14lib/vdso: Mark do_hres() and do_coarse() as __always_inlineAndrei Vagin
Performance numbers for Intel(R) Core(TM) i5-6300U CPU @ 2.40GHz (more clock_gettime() cycles - the better): clock | before | after | diff ---------------------------------------------------------- monotonic | 153222105 | 166775025 | 8.8% monotonic-coarse | 671557054 | 691513017 | 3.0% monotonic-raw | 147116067 | 161057395 | 9.5% boottime | 153446224 | 166962668 | 9.1% The improvement for arm64 for monotonic and boottime is around 3.5%. clock | before | after | diff ================================================== monotonic 17326692 17951770 3.6% monotonic-coarse 43624027 44215292 1.3% monotonic-raw 17541809 17554932 0.1% boottime 17334982 17954361 3.5% [ tglx: Avoid the goto ] Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191112012724.250792-3-dima@arista.com
2020-01-14lib/vdso: Add unlikely() hint into vdso_read_begin()Andrei Vagin
Place the branch with no concurrent write before the contended case. Performance numbers for Intel(R) Core(TM) i5-6300U CPU @ 2.40GHz (more clock_gettime() cycles - the better): | before | after ----------------------------------- | 150252214 | 153242367 | 150301112 | 153324800 | 150392773 | 153125401 | 150373957 | 153399355 | 150303157 | 153489417 | 150365237 | 153494270 ----------------------------------- avg | 150331408 | 153345935 diff % | 2 | 0 ----------------------------------- stdev % | 0.3 | 0.1 Co-developed-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lore.kernel.org/r/20191112012724.250792-2-dima@arista.com
2020-01-14lib/vdso: Avoid duplication in __cvdso_clock_getres()Christophe Leroy
VDSO_HRES and VDSO_RAW clocks are handled the same way. Avoid the code duplication. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/fdf1a968a8f7edd61456f1689ac44082ebb19c15.1577111367.git.christophe.leroy@c-s.fr
2020-01-14lib/vdso: Let do_coarse() return 0 to simplify the callsiteChristophe Leroy
do_coarse() is similar to do_hres() except that it never fails. Change its type to int instead of void and let it always return success (0) to simplify the call site. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/21e8afa38c02ca8672c2690307383507fe63b454.1577111367.git.christophe.leroy@c-s.fr
2020-01-14x86/vdso: Remove unused VDSO_HAS_32BIT_FALLBACKVincenzo Frascino
VDSO_HAS_32BIT_FALLBACK has been removed from the core since the architectures that support the generic vDSO library have been converted to support the 32 bit fallbacks. Remove unused VDSO_HAS_32BIT_FALLBACK from x86 vdso. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20190830135902.20861-9-vincenzo.frascino@arm.com
2020-01-14mips: vdso: Remove unused VDSO_HAS_32BIT_FALLBACKVincenzo Frascino
VDSO_HAS_32BIT_FALLBACK has been removed from the core since the architectures that support the generic vDSO library have been converted to support the 32 bit fallbacks. Remove unused VDSO_HAS_32BIT_FALLBACK from mips vdso. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Paul Burton <paul.burton@mips.com> Link: https://lore.kernel.org/r/20190830135902.20861-8-vincenzo.frascino@arm.com
2020-01-14arm64: compat: vdso: Remove unused VDSO_HAS_32BIT_FALLBACKVincenzo Frascino
VDSO_HAS_32BIT_FALLBACK has been removed from the core since the architectures that support the generic vDSO library have been converted to support the 32 bit fallbacks. Remove unused VDSO_HAS_32BIT_FALLBACK from arm64 compat vdso. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20190830135902.20861-7-vincenzo.frascino@arm.com
2020-01-14lib/vdso: Remove checks on return value for 32 bit vDSOVincenzo Frascino
Since all the architectures that support the generic vDSO library have been converted to support the 32 bit fallbacks it is not required anymore to check the return value of __cvdso_clock_get*time32_common() before updating the old_timespec fields. Remove the related checks from the generic vdso library. References: c60a32ea4f45 ("lib/vdso/32: Provide legacy syscall fallbacks") Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20190830135902.20861-6-vincenzo.frascino@arm.com
2020-01-14lib/vdso: Remove VDSO_HAS_32BIT_FALLBACKVincenzo Frascino
VDSO_HAS_32BIT_FALLBACK was introduced to address a regression which caused seccomp to deny access to the applications to clock_gettime64() and clock_getres64() because they are not enabled in the existing filters. The purpose of VDSO_HAS_32BIT_FALLBACK was to simplify the conditional implementation of __cvdso_clock_get*time32() variants. Now that all the architectures that support the generic vDSO library have been converted to support the 32 bit fallbacks the conditional can be removed. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20190830135902.20861-5-vincenzo.frascino@arm.com References: c60a32ea4f45 ("lib/vdso/32: Provide legacy syscall fallbacks")
2020-01-14lib/vdso: Build 32 bit specific functions in the right contextVincenzo Frascino
clock_gettime32 and clock_getres_time32 should be compiled only with a 32 bit vdso library. Exclude these symbols when BUILD_VDSO32 is not defined. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20190830135902.20861-3-vincenzo.frascino@arm.com
2020-01-14ARM: vdso: Set BUILD_VDSO32 and provide 32bit fallbacksThomas Gleixner
Setting BUILD_VDSO32 is required to expose the legacy 32bit interfaces in the generic VDSO code which are going to be hidden behind an #ifdef BUILD_VDSO32. The 32bit fallbacks are necessary to remove the existing VDSO_HAS_32BIT_FALLBACK hackery. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/87tv4zq9dc.fsf@nanos.tec.linutronix.de
2020-01-14arm64: compat: vdso: Expose BUILD_VDSO32Vincenzo Frascino
clock_gettime32 and clock_getres_time32 should be compiled only with the 32 bit vdso library. Expose BUILD_VDSO32 when arm64 compat is compiled, to provide an indication to the generic library to include these symbols. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20190830135902.20861-2-vincenzo.frascino@arm.com
2020-01-14USB: serial: opticon: fix control-message timeoutsJohan Hovold
The driver was issuing synchronous uninterruptible control requests without using a timeout. This could lead to the driver hanging on open() or tiocmset() due to a malfunctioning (or malicious) device until the device is physically disconnected. The USB upper limit of five seconds per request should be more than enough. Fixes: 309a057932ab ("USB: opticon: add rts and cts support") Cc: stable <stable@vger.kernel.org> # 2.6.39 Cc: Martin Jansen <martin.jansen@opticon.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Johan Hovold <johan@kernel.org>
2020-01-14m68k: Implement copy_thread_tls()Geert Uytterhoeven
This is required for clone3(), which passes the TLS value through a struct rather than a register. As do_fork() is only available if CONFIG_HAVE_COPY_THREAD_TLS is set, m68k_clone() must be changed to call _do_fork() directly. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Greg Ungerer <gerg@linux-m68k.org> Link: https://lore.kernel.org/r/20200113103040.23661-1-geert@linux-m68k.org
2020-01-14ALSA: usb-audio: fix sync-ep altsetting sanity checkJohan Hovold
The altsetting sanity check in set_sync_ep_implicit_fb_quirk() was checking for there to be at least one altsetting but then went on to access the second one, which may not exist. This could lead to random slab data being used to initialise the sync endpoint in snd_usb_add_endpoint(). Fixes: c75a8a7ae565 ("ALSA: snd-usb: add support for implicit feedback") Fixes: ca10a7ebdff1 ("ALSA: usb-audio: FT C400 sync playback EP to capture EP") Fixes: 5e35dc0338d8 ("ALSA: usb-audio: add implicit fb quirk for Behringer UFX1204") Fixes: 17f08b0d9aaf ("ALSA: usb-audio: add implicit fb quirk for Axe-Fx II") Fixes: 103e9625647a ("ALSA: usb-audio: simplify set_sync_ep_implicit_fb_quirk") Cc: stable <stable@vger.kernel.org> # 3.5 Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20200114083953.1106-1-johan@kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-01-14parisc: fix map_pages() to actually populate upper directoryMike Rapoport
The commit d96885e277b5 ("parisc: use pgtable-nopXd instead of 4level-fixup") converted PA-RISC to use folded page tables, but it missed the conversion of pgd_populate() to pud_populate() in maps_pages() function. This caused the upper page table directory to remain empty and the system would crash as a result. Using pud_populate() that actually populates the page table instead of dummy pgd_populate() fixes the issue. Fixes: d96885e277b5 ("parisc: use pgtable-nopXd instead of 4level-fixup") Reported-by: Meelis Roos <mroos@linux.ee> Reported-by: Jeroen Roovers <jer@gentoo.org> Reported-by: Mikulas Patocka <mpatocka@redhat.com> Tested-by: Jeroen Roovers <jer@gentoo.org> Tested-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Helge Deller <deller@gmx.de>
2020-01-14parisc: Use proper printk format for resource_size_tKrzysztof Kozlowski
resource_size_t should be printed with its own size-independent format to fix warnings when compiling on 64-bit platform (e.g. with COMPILE_TEST): arch/parisc/kernel/drivers.c: In function 'print_parisc_device': arch/parisc/kernel/drivers.c:892:9: warning: format '%p' expects argument of type 'void *', but argument 4 has type 'resource_size_t {aka unsigned int}' [-Wformat=] Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Helge Deller <deller@gmx.de>
2020-01-14xfrm: interface: do not confirm neighbor when do pmtu updateXu Wang
When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end, we should not call dst_confirm_neigh() as there is no two-way communication. Signed-off-by: Xu Wang <vulab@iscas.ac.cn> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2020-01-14xfrm interface: fix packet tx through bpf_redirect()Nicolas Dichtel
With an ebpf program that redirects packets through a xfrm interface, packets are dropped because no dst is attached to skb. This could also be reproduced with an AF_PACKET socket, with the following python script (xfrm1 is a xfrm interface): import socket send_s = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, 0) # scapy # p = IP(src='10.100.0.2', dst='10.200.0.1')/ICMP(type='echo-request') # raw(p) req = b'E\x00\x00\x1c\x00\x01\x00\x00@\x01e\xb2\nd\x00\x02\n\xc8\x00\x01\x08\x00\xf7\xff\x00\x00\x00\x00' send_s.sendto(req, ('xfrm1', 0x800, 0, 0)) It was also not possible to send an ip packet through an AF_PACKET socket because a LL header was expected. Let's remove those LL header constraints. Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2020-01-14vti[6]: fix packet tx through bpf_redirect()Nicolas Dichtel
With an ebpf program that redirects packets through a vti[6] interface, the packets are dropped because no dst is attached. This could also be reproduced with an AF_PACKET socket, with the following python script (vti1 is an ip_vti interface): import socket send_s = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, 0) # scapy # p = IP(src='10.100.0.2', dst='10.200.0.1')/ICMP(type='echo-request') # raw(p) req = b'E\x00\x00\x1c\x00\x01\x00\x00@\x01e\xb2\nd\x00\x02\n\xc8\x00\x01\x08\x00\xf7\xff\x00\x00\x00\x00' send_s.sendto(req, ('vti1', 0x800, 0, 0)) Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2020-01-14drm/i915/pmu: Do not use colons or dashes in PMU namesTvrtko Ursulin
We use PCI device path in the registered PMU name in order to distinguish between multiple GPUs. But since tools/perf reserves a special meaning to dash and colon characters we need to transliterate them to something else. We choose an underscore. v2: * Use strreplace. (Chris) * Dashes are not good either. (Chris) Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reported-by: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com> Fixes: 05488673a4d4 ("drm/i915/pmu: Support multiple GPUs") Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20200110113253.12535-1-tvrtko.ursulin@linux.intel.com (cherry picked from commit aebf3b521b34ca49f6e81c667f92364334ca27cf) Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
2020-01-13NFC: pn533: fix bulk-message timeoutJohan Hovold
The driver was doing a synchronous uninterruptible bulk-transfer without using a timeout. This could lead to the driver hanging on probe due to a malfunctioning (or malicious) device until the device is physically disconnected. While sleeping in probe the driver prevents other devices connected to the same hub from being added to (or removed from) the bus. An arbitrary limit of five seconds should be more than enough. Fixes: dbafc28955fa ("NFC: pn533: don't send USB data off of the stack") Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-01-13qmi_wwan: Add support for Quectel RM500QKristian Evensen
RM500Q is a 5G module from Quectel, supporting both standalone and non-standalone modes. The normal Quectel quirks apply (DTR and dynamic interface numbers). Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com> Acked-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-01-13Merge tag 'Intel-CVE-2019-14615' from bundle by Akeem Abodunrin.Linus Torvalds
Merge Intel Gen9 graphics fix from Akeem Abodunrin: "Insufficient control flow in certain data structures for some Intel Processors with Intel Processor Graphics may allow an unauthenticated user to potentially enable information disclosure via local access This provides mitigation for Gen9 hardware. Note that Gen8 is not impacted due to a previously implemented workaround. The mitigation involves using an existing hardware feature to forcibly clear down all EU state at each context switch" * tag 'Intel-CVE-2019-14615' of emailed bundle from Akeem G Abodunrin <akeem.g.abodunrin@intel.com>: drm/i915/gen9: Clear residual context state on context switch
2020-01-13net: macb: fix for fixed-link modeMilind Parab
This patch fix the issue with fixed link. With fixed-link device opening fails due to macb_phylink_connect not handling fixed-link mode, in which case no MAC-PHY connection is needed and phylink_connect return success (0), however in current driver attempt is made to search and connect to PHY even for fixed-link. Fixes: 7897b071ac3b ("net: macb: convert to phylink") Signed-off-by: Milind Parab <mparab@cadence.com> Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-01-13io_uring: don't setup async context for read/write fixedJens Axboe
We don't need it, and if we have it, then the retry handler will attempt to copy the non-existent iovec with the inline iovec, with a segment count that doesn't make sense. Fixes: f67676d160c6 ("io_uring: ensure async punted read/write requests copy iovec") Reported-by: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-13mm: khugepaged: add trace status description for SCAN_PAGE_HAS_PRIVATEYang Shi
Commit 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") introduced a new khugepaged scan result: SCAN_PAGE_HAS_PRIVATE, but the corresponding description for trace events were not added. Link: http://lkml.kernel.org/r/1574793844-2914-1-git-send-email-yang.shi@linux.alibaba.com Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Cc: Song Liu <songliubraving@fb.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13mm: memcg/slab: call flush_memcg_workqueue() only if memcg workqueue is validAdrian Huang
When booting with amd_iommu=off, the following WARNING message appears: AMD-Vi: AMD IOMMU disabled on kernel command-line ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/workqueue.c:2772 flush_workqueue+0x42e/0x450 Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.5.0-rc3-amd-iommu #6 Hardware name: Lenovo ThinkSystem SR655-2S/7D2WRCZ000, BIOS D8E101L-1.00 12/05/2019 RIP: 0010:flush_workqueue+0x42e/0x450 Code: ff 0f 0b e9 7a fd ff ff 4d 89 ef e9 33 fe ff ff 0f 0b e9 7f fd ff ff 0f 0b e9 bc fd ff ff 0f 0b e9 a8 fd ff ff e8 52 2c fe ff <0f> 0b 31 d2 48 c7 c6 e0 88 c5 95 48 c7 c7 d8 ad f0 95 e8 19 f5 04 Call Trace: kmem_cache_destroy+0x69/0x260 iommu_go_to_state+0x40c/0x5ab amd_iommu_prepare+0x16/0x2a irq_remapping_prepare+0x36/0x5f enable_IR_x2apic+0x21/0x172 default_setup_apic_routing+0x12/0x6f apic_intr_mode_init+0x1a1/0x1f1 x86_late_time_init+0x17/0x1c start_kernel+0x480/0x53f secondary_startup_64+0xb6/0xc0 ---[ end trace 30894107c3749449 ]--- x2apic: IRQ remapping doesn't support X2APIC mode x2apic disabled The warning is caused by the calling of 'kmem_cache_destroy()' in free_iommu_resources(). Here is the call path: free_iommu_resources kmem_cache_destroy flush_memcg_workqueue flush_workqueue The root cause is that the IOMMU subsystem runs before the workqueue subsystem, which the variable 'wq_online' is still 'false'. This leads to the statement 'if (WARN_ON(!wq_online))' in flush_workqueue() is 'true'. Since the variable 'memcg_kmem_cache_wq' is not allocated during the time, it is unnecessary to call flush_memcg_workqueue(). This prevents the WARNING message triggered by flush_workqueue(). Link: http://lkml.kernel.org/r/20200103085503.1665-1-ahuang12@lenovo.com Fixes: 92ee383f6daab ("mm: fix race between kmem_cache destroy, create and deactivate") Signed-off-by: Adrian Huang <ahuang12@lenovo.com> Reported-by: Xiaochun Lee <lixc17@lenovo.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13mm/page-writeback.c: improve arithmetic divisionsWen Yang
Use div64_ul() instead of do_div() if the divisor is unsigned long, to avoid truncation to 32-bit on 64-bit platforms. Link: http://lkml.kernel.org/r/20200102081442.8273-4-wenyang@linux.alibaba.com Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Qian Cai <cai@lca.pw> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13mm/page-writeback.c: use div64_ul() for u64-by-unsigned-long divideWen Yang
The two variables 'numerator' and 'denominator', though they are declared as long, they should actually be unsigned long (according to the implementation of the fprop_fraction_percpu() function) And do_div() does a 64-by-32 division, while the divisor 'denominator' is unsigned long, thus 64-bit on 64-bit platforms. Hence the proper function to call is div64_ul(). Link: http://lkml.kernel.org/r/20200102081442.8273-3-wenyang@linux.alibaba.com Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Qian Cai <cai@lca.pw> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13mm/page-writeback.c: avoid potential division by zero in wb_min_max_ratio()Wen Yang
Patch series "use div64_ul() instead of div_u64() if the divisor is unsigned long". We were first inspired by commit b0ab99e7736a ("sched: Fix possible divide by zero in avg_atom () calculation"), then refer to the recently analyzed mm code, we found this suspicious place. 201 if (min) { 202 min *= this_bw; 203 do_div(min, tot_bw); 204 } And we also disassembled and confirmed it: /usr/src/debug/kernel-4.9.168-016.ali3000/linux-4.9.168-016.ali3000.alios7.x86_64/mm/page-writeback.c: 201 0xffffffff811c37da <__wb_calc_thresh+234>: xor %r10d,%r10d 0xffffffff811c37dd <__wb_calc_thresh+237>: test %rax,%rax 0xffffffff811c37e0 <__wb_calc_thresh+240>: je 0xffffffff811c3800 <__wb_calc_thresh+272> /usr/src/debug/kernel-4.9.168-016.ali3000/linux-4.9.168-016.ali3000.alios7.x86_64/mm/page-writeback.c: 202 0xffffffff811c37e2 <__wb_calc_thresh+242>: imul %r8,%rax /usr/src/debug/kernel-4.9.168-016.ali3000/linux-4.9.168-016.ali3000.alios7.x86_64/mm/page-writeback.c: 203 0xffffffff811c37e6 <__wb_calc_thresh+246>: mov %r9d,%r10d ---> truncates it to 32 bits here 0xffffffff811c37e9 <__wb_calc_thresh+249>: xor %edx,%edx 0xffffffff811c37eb <__wb_calc_thresh+251>: div %r10 0xffffffff811c37ee <__wb_calc_thresh+254>: imul %rbx,%rax 0xffffffff811c37f2 <__wb_calc_thresh+258>: shr $0x2,%rax 0xffffffff811c37f6 <__wb_calc_thresh+262>: mul %rcx 0xffffffff811c37f9 <__wb_calc_thresh+265>: shr $0x2,%rdx 0xffffffff811c37fd <__wb_calc_thresh+269>: mov %rdx,%r10 This series uses div64_ul() instead of div_u64() if the divisor is unsigned long, to avoid truncation to 32-bit on 64-bit platforms. This patch (of 3): The variables 'min' and 'max' are unsigned long and do_div truncates them to 32 bits, which means it can test non-zero and be truncated to zero for division. Fix this issue by using div64_ul() instead. Link: http://lkml.kernel.org/r/20200102081442.8273-2-wenyang@linux.alibaba.com Fixes: 693108a8a667 ("writeback: make bdi->min/max_ratio handling cgroup writeback aware") Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Qian Cai <cai@lca.pw> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13mm, debug_pagealloc: don't rely on static keys too earlyVlastimil Babka
Commit 96a2b03f281d ("mm, debug_pagelloc: use static keys to enable debugging") has introduced a static key to reduce overhead when debug_pagealloc is compiled in but not enabled. It relied on the assumption that jump_label_init() is called before parse_early_param() as in start_kernel(), so when the "debug_pagealloc=on" option is parsed, it is safe to enable the static key. However, it turns out multiple architectures call parse_early_param() earlier from their setup_arch(). x86 also calls jump_label_init() even earlier, so no issue was found while testing the commit, but same is not true for e.g. ppc64 and s390 where the kernel would not boot with debug_pagealloc=on as found by our QA. To fix this without tricky changes to init code of multiple architectures, this patch partially reverts the static key conversion from 96a2b03f281d. Init-time and non-fastpath calls (such as in arch code) of debug_pagealloc_enabled() will again test a simple bool variable. Fastpath mm code is converted to a new debug_pagealloc_enabled_static() variant that relies on the static key, which is enabled in a well-defined point in mm_init() where it's guaranteed that jump_label_init() has been called, regardless of architecture. [sfr@canb.auug.org.au: export _debug_pagealloc_enabled_early] Link: http://lkml.kernel.org/r/20200106164944.063ac07b@canb.auug.org.au Link: http://lkml.kernel.org/r/20191219130612.23171-1-vbabka@suse.cz Fixes: 96a2b03f281d ("mm, debug_pagelloc: use static keys to enable debugging") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Qian Cai <cai@lca.pw> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13mm: memcg/slab: fix percpu slab vmstats flushingRoman Gushchin
Currently slab percpu vmstats are flushed twice: during the memcg offlining and just before freeing the memcg structure. Each time percpu counters are summed, added to the atomic counterparts and propagated up by the cgroup tree. The second flushing is required due to how recursive vmstats are implemented: counters are batched in percpu variables on a local level, and once a percpu value is crossing some predefined threshold, it spills over to atomic values on the local and each ascendant levels. It means that without flushing some numbers cached in percpu variables will be dropped on floor each time a cgroup is destroyed. And with uptime the error on upper levels might become noticeable. The first flushing aims to make counters on ancestor levels more precise. Dying cgroups may resume in the dying state for a long time. After kmem_cache reparenting which is performed during the offlining slab counters of the dying cgroup don't have any chances to be updated, because any slab operations will be performed on the parent level. It means that the inaccuracy caused by percpu batching will not decrease up to the final destruction of the cgroup. By the original idea flushing slab counters during the offlining should minimize the visible inaccuracy of slab counters on the parent level. The problem is that percpu counters are not zeroed after the first flushing. So every cached percpu value is summed twice. It creates a small error (up to 32 pages per cpu, but usually less) which accumulates on parent cgroup level. After creating and destroying of thousands of child cgroups, slab counter on parent level can be way off the real value. For now, let's just stop flushing slab counters on memcg offlining. It can't be done correctly without scheduling a work on each cpu: reading and zeroing it during css offlining can race with an asynchronous update, which doesn't expect values to be changed underneath. With this change, slab counters on parent level will become eventually consistent. Once all dying children are gone, values are correct. And if not, the error is capped by 32 * NR_CPUS pages per dying cgroup. It's not perfect, as slab are reparented, so any updates after the reparenting will happen on the parent level. It means that if a slab page was allocated, a counter on child level was bumped, then the page was reparented and freed, the annihilation of positive and negative counter values will not happen until the child cgroup is released. It makes slab counters different from others, and it might want us to implement flushing in a correct form again. But it's also a question of performance: scheduling a work on each cpu isn't free, and it's an open question if the benefit of having more accurate counters is worth it. We might also consider flushing all counters on offlining, not only slab counters. So let's fix the main problem now: make the slab counters eventually consistent, so at least the error won't grow with uptime (or more precisely the number of created and destroyed cgroups). And think about the accuracy of counters separately. Link: http://lkml.kernel.org/r/20191220042728.1045881-1-guro@fb.com Fixes: bee07b33db78 ("mm: memcontrol: flush percpu slab vmstats on kmem offlining") Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13mm/shmem.c: thp, shmem: fix conflict of above-47bit hint address and PMD ↵Kirill A. Shutemov
alignment Shmem/tmpfs tries to provide THP-friendly mappings if huge pages are enabled. But it doesn't work well with above-47bit hint address. Normally, the kernel doesn't create userspace mappings above 47-bit, even if the machine allows this (such as with 5-level paging on x86-64). Not all user space is ready to handle wide addresses. It's known that at least some JIT compilers use higher bits in pointers to encode their information. Userspace can ask for allocation from full address space by specifying hint address (with or without MAP_FIXED) above 47-bits. If the application doesn't need a particular address, but wants to allocate from whole address space it can specify -1 as a hint address. Unfortunately, this trick breaks THP alignment in shmem/tmp: shmem_get_unmapped_area() would not try to allocate PMD-aligned area if *any* hint address specified. This can be fixed by requesting the aligned area if the we failed to allocated at user-specified hint address. The request with inflated length will also take the user-specified hint address. This way we will not lose an allocation request from the full address space. [kirill@shutemov.name: fold in a fixup] Link: http://lkml.kernel.org/r/20191223231309.t6bh5hkbmokihpfu@box Link: http://lkml.kernel.org/r/20191220142548.7118-3-kirill.shutemov@linux.intel.com Fixes: b569bab78d8d ("x86/mm: Prepare to expose larger address space to userspace") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "Willhalm, Thomas" <thomas.willhalm@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "Bruggeman, Otto G" <otto.g.bruggeman@intel.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13mm/huge_memory.c: thp: fix conflict of above-47bit hint address and PMD ↵Kirill A. Shutemov
alignment Patch series "Fix two above-47bit hint address vs. THP bugs". The two get_unmapped_area() implementations have to be fixed to provide THP-friendly mappings if above-47bit hint address is specified. This patch (of 2): Filesystems use thp_get_unmapped_area() to provide THP-friendly mappings. For DAX in particular. Normally, the kernel doesn't create userspace mappings above 47-bit, even if the machine allows this (such as with 5-level paging on x86-64). Not all user space is ready to handle wide addresses. It's known that at least some JIT compilers use higher bits in pointers to encode their information. Userspace can ask for allocation from full address space by specifying hint address (with or without MAP_FIXED) above 47-bits. If the application doesn't need a particular address, but wants to allocate from whole address space it can specify -1 as a hint address. Unfortunately, this trick breaks thp_get_unmapped_area(): the function would not try to allocate PMD-aligned area if *any* hint address specified. Modify the routine to handle it correctly: - Try to allocate the space at the specified hint address with length padding required for PMD alignment. - If failed, retry without length padding (but with the same hint address); - If the returned address matches the hint address return it. - Otherwise, align the address as required for THP and return. The user specified hint address is passed down to get_unmapped_area() so above-47bit hint address will be taken into account without breaking alignment requirements. Link: http://lkml.kernel.org/r/20191220142548.7118-2-kirill.shutemov@linux.intel.com Fixes: b569bab78d8d ("x86/mm: Prepare to expose larger address space to userspace") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Thomas Willhalm <thomas.willhalm@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: "Bruggeman, Otto G" <otto.g.bruggeman@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13mm/memory_hotplug: don't free usage map when removing a re-added early sectionDavid Hildenbrand
When we remove an early section, we don't free the usage map, as the usage maps of other sections are placed into the same page. Once the section is removed, it is no longer an early section (especially, the memmap is freed). When we re-add that section, the usage map is reused, however, it is no longer an early section. When removing that section again, we try to kfree() a usage map that was allocated during early boot - bad. Let's check against PageReserved() to see if we are dealing with an usage map that was allocated during boot. We could also check against !(PageSlab(usage_page) || PageCompound(usage_page)), but PageReserved() is cleaner. Can be triggered using memtrace under ppc64/powernv: $ mount -t debugfs none /sys/kernel/debug/ $ echo 0x20000000 > /sys/kernel/debug/powerpc/memtrace/enable $ echo 0x20000000 > /sys/kernel/debug/powerpc/memtrace/enable ------------[ cut here ]------------ kernel BUG at mm/slub.c:3969! Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=3D64K MMU=3DHash SMP NR_CPUS=3D2048 NUMA PowerNV Modules linked in: CPU: 0 PID: 154 Comm: sh Not tainted 5.5.0-rc2-next-20191216-00005-g0be1dba7b7c0 #61 NIP kfree+0x338/0x3b0 LR section_deactivate+0x138/0x200 Call Trace: section_deactivate+0x138/0x200 __remove_pages+0x114/0x150 arch_remove_memory+0x3c/0x160 try_remove_memory+0x114/0x1a0 __remove_memory+0x20/0x40 memtrace_enable_set+0x254/0x850 simple_attr_write+0x138/0x160 full_proxy_write+0x8c/0x110 __vfs_write+0x38/0x70 vfs_write+0x11c/0x2a0 ksys_write+0x84/0x140 system_call+0x5c/0x68 ---[ end trace 4b053cbd84e0db62 ]--- The first invocation will offline+remove memory blocks. The second invocation will first add+online them again, in order to offline+remove them again (usually we are lucky and the exact same memory blocks will get "reallocated"). Tested on powernv with boot memory: The usage map will not get freed. Tested on x86-64 with DIMMs: The usage map will get freed. Using Dynamic Memory under a Power DLAPR can trigger it easily. Triggering removal (I assume after previously removed+re-added) of memory from the HMC GUI can crash the kernel with the same call trace and is fixed by this patch. Link: http://lkml.kernel.org/r/20191217104637.5509-1-david@redhat.com Fixes: 326e1b8f83a4 ("mm/sparsemem: introduce a SECTION_IS_EARLY flag") Signed-off-by: David Hildenbrand <david@redhat.com> Tested-by: Pingfan Liu <piliu@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13mm, thp: tweak reclaim/compaction effort of local-only and all-node allocationsVlastimil Babka
THP page faults now attempt a __GFP_THISNODE allocation first, which should only compact existing free memory, followed by another attempt that can allocate from any node using reclaim/compaction effort specified by global defrag setting and madvise. This patch makes the following changes to the scheme: - Before the patch, the first allocation relies on a check for pageblock order and __GFP_IO to prevent excessive reclaim. This however affects also the second attempt, which is not limited to single node. Instead of that, reuse the existing check for costly order __GFP_NORETRY allocations, and make sure the first THP attempt uses __GFP_NORETRY. As a side-effect, all costly order __GFP_NORETRY allocations will bail out if compaction needs reclaim, while previously they only bailed out when compaction was deferred due to previous failures. This should be still acceptable within the __GFP_NORETRY semantics. - Before the patch, the second allocation attempt (on all nodes) was passing __GFP_NORETRY. This is redundant as the check for pageblock order (discussed above) was stronger. It's also contrary to madvise(MADV_HUGEPAGE) which means some effort to allocate THP is requested. After this patch, the second attempt doesn't pass __GFP_THISNODE nor __GFP_NORETRY. To sum up, THP page faults now try the following attempts: 1. local node only THP allocation with no reclaim, just compaction. 2. for madvised VMA's or when synchronous compaction is enabled always - THP allocation from any node with effort determined by global defrag setting and VMA madvise 3. fallback to base pages on any node Link: http://lkml.kernel.org/r/08a3f4dd-c3ce-0009-86c5-9ee51aba8557@suse.cz Fixes: b39d0ee2632d ("mm, page_alloc: avoid expensive reclaim when compaction may not succeed") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-13Merge branch 'md-next' of ↵Jens Axboe
git://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-5.6/drivers Pull MD changes from Song. * 'md-next' of git://git.kernel.org/pub/scm/linux/kernel/git/song/md: md/raid1: introduce wait_for_serialization md/raid1: use bucket based mechanism for IO serialization md: introduce a new struct for IO serialization md: don't destroy serial_info_pool if serialize_policy is true raid1: serialize the overlap write md: reorgnize mddev_create/destroy_serial_pool md: add serialize_policy sysfs node for raid1 md: prepare for enable raid1 io serialization md: fix a typo s/creat/create md: rename wb stuffs raid5: remove worker_cnt_per_group argument from alloc_thread_groups md/raid6: fix algorithm choice under larger PAGE_SIZE raid6/test: fix a compilation warning raid6/test: fix a compilation error md-bitmap: small cleanups
2020-01-13btrfs: relocation: fix reloc_root lifespan and accessQu Wenruo
[BUG] There are several different KASAN reports for balance + snapshot workloads. Involved call paths include: should_ignore_root+0x54/0xb0 [btrfs] build_backref_tree+0x11af/0x2280 [btrfs] relocate_tree_blocks+0x391/0xb80 [btrfs] relocate_block_group+0x3e5/0xa00 [btrfs] btrfs_relocate_block_group+0x240/0x4d0 [btrfs] btrfs_relocate_chunk+0x53/0xf0 [btrfs] btrfs_balance+0xc91/0x1840 [btrfs] btrfs_ioctl_balance+0x416/0x4e0 [btrfs] btrfs_ioctl+0x8af/0x3e60 [btrfs] do_vfs_ioctl+0x831/0xb10 create_reloc_root+0x9f/0x460 [btrfs] btrfs_reloc_post_snapshot+0xff/0x6c0 [btrfs] create_pending_snapshot+0xa9b/0x15f0 [btrfs] create_pending_snapshots+0x111/0x140 [btrfs] btrfs_commit_transaction+0x7a6/0x1360 [btrfs] btrfs_mksubvol+0x915/0x960 [btrfs] btrfs_ioctl_snap_create_transid+0x1d5/0x1e0 [btrfs] btrfs_ioctl_snap_create_v2+0x1d3/0x270 [btrfs] btrfs_ioctl+0x241b/0x3e60 [btrfs] do_vfs_ioctl+0x831/0xb10 btrfs_reloc_pre_snapshot+0x85/0xc0 [btrfs] create_pending_snapshot+0x209/0x15f0 [btrfs] create_pending_snapshots+0x111/0x140 [btrfs] btrfs_commit_transaction+0x7a6/0x1360 [btrfs] btrfs_mksubvol+0x915/0x960 [btrfs] btrfs_ioctl_snap_create_transid+0x1d5/0x1e0 [btrfs] btrfs_ioctl_snap_create_v2+0x1d3/0x270 [btrfs] btrfs_ioctl+0x241b/0x3e60 [btrfs] do_vfs_ioctl+0x831/0xb10 [CAUSE] All these call sites are only relying on root->reloc_root, which can undergo btrfs_drop_snapshot(), and since we don't have real refcount based protection to reloc roots, we can reach already dropped reloc root, triggering KASAN. [FIX] To avoid such access to unstable root->reloc_root, we should check BTRFS_ROOT_DEAD_RELOC_TREE bit first. This patch introduces wrappers that provide the correct way to check the bit with memory barriers protection. Most callers don't distinguish merged reloc tree and no reloc tree. The only exception is should_ignore_root(), as merged reloc tree can be ignored, while no reloc tree shouldn't. [CRITICAL SECTION ANALYSIS] Although test_bit()/set_bit()/clear_bit() doesn't imply a barrier, the DEAD_RELOC_TREE bit has extra help from transaction as a higher level barrier, the lifespan of root::reloc_root and DEAD_RELOC_TREE bit are: NULL: reloc_root is NULL PTR: reloc_root is not NULL 0: DEAD_RELOC_ROOT bit not set DEAD: DEAD_RELOC_ROOT bit set (NULL, 0) Initial state __ | /\ Section A btrfs_init_reloc_root() \/ | __ (PTR, 0) reloc_root initialized /\ | | btrfs_update_reloc_root() | Section B | | (PTR, DEAD) reloc_root has been merged \/ | __ === btrfs_commit_transaction() ==================== | /\ clean_dirty_subvols() | | | Section C (NULL, DEAD) reloc_root cleanup starts \/ | __ btrfs_drop_snapshot() /\ | | Section D (NULL, 0) Back to initial state \/ Every have_reloc_root() or test_bit(DEAD_RELOC_ROOT) caller holds transaction handle, so none of such caller can cross transaction boundary. In Section A, every caller just found no DEAD bit, and grab reloc_root. In the cross section A-B, caller may get no DEAD bit, but since reloc_root is still completely valid thus accessing reloc_root is completely safe. No test_bit() caller can cross the boundary of Section B and Section C. In Section C, every caller found the DEAD bit, so no one will access reloc_root. In the cross section C-D, either caller gets the DEAD bit set, avoiding access reloc_root no matter if it's safe or not. Or caller get the DEAD bit cleared, then access reloc_root, which is already NULL, nothing will be wrong. The memory write barriers are between the reloc_root updates and bit set/clear, the pairing read side is before test_bit. Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Fixes: d2311e698578 ("btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ barriers ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-13md/raid1: introduce wait_for_serializationGuoqing Jiang
Previously, we call check_and_add_serial when serialization is enabled for write IO, but it could allocate and free memory back and forth. Now, let's just get an element from memory pool with the new function, then insert node to rb tree if no collision happens. Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Song Liu <songliubraving@fb.com>
2020-01-13md/raid1: use bucket based mechanism for IO serializationGuoqing Jiang
Since raid1 had already used bucket based mechanism to reduce the conflict between write IO and resync IO, it is possible to speed up performance for io serialization with refer to the same mechanism. To align with the barrier bucket mechanism, we created arrays (with the same number of BARRIER_BUCKETS_NR) for spinlock, rb tree and waitqueue. Then we can reduce lock competition with multiple spinlocks, boost search performance with multiple rb trees and also reduce thundering herd problem with multiple waitqueues. Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Song Liu <songliubraving@fb.com>
2020-01-13md: introduce a new struct for IO serializationGuoqing Jiang
Obviously, IO serialization could cause the degradation of performance a lot. In order to reduce the degradation, so a rb interval tree is added in raid1 to speed up the check of collision. So, a rb root is needed in md_rdev, then abstract all the serialize related members to a new struct (serial_in_rdev), embed it into md_rdev. Of course, we need to free the struct if it is not needed anymore, so rdev/rdevs_uninit_serial are added accordingly. And they should be called when destroty memory pool or can't alloc memory. And we need to consider to call mddev_destroy_serial_pool in case serialize_policy/write-behind is disabled, bitmap is destroyed or in __md_stop_writes. Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Song Liu <songliubraving@fb.com>
2020-01-13md: don't destroy serial_info_pool if serialize_policy is trueGuoqing Jiang
The serial_info_pool is needed if array sets serialize_policy to true, so don't destroy it. Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Song Liu <songliubraving@fb.com>
2020-01-13raid1: serialize the overlap writeGuoqing Jiang
Before dispatch write bio, raid1 array which enables serialize_policy need to check if overlap exists between this bio and previous on-flying bios. If there is overlap, then it has to wait until the collision is disappeared. Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Song Liu <songliubraving@fb.com>
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