user/sven/linux.git/include, branch v4.19.92

cpufreq: Avoid leaving stale IRQ work items during CPU offline

2019-12-31T15:36:22Z

commit 85572c2c4a45a541e880e087b5b17a48198b2416 upstream. The scheduler code calling cpufreq_update_util() may run during CPU offline on the target CPU after the IRQ work lists have been flushed for it, so the target CPU should be prevented from running code that may queue up an IRQ work item on it at that point. Unfortunately, that may not be the case if dvfs_possible_from_any_cpu is set for at least one cpufreq policy in the system, because that allows the CPU going offline to run the utilization update callback of the cpufreq governor on behalf of another (online) CPU in some cases. If that happens, the cpufreq governor callback may queue up an IRQ work on the CPU running it, which is going offline, and the IRQ work may not be flushed after that point. Moreover, that IRQ work cannot be flushed until the "offlining" CPU goes back online, so if any other CPU calls irq_work_sync() to wait for the completion of that IRQ work, it will have to wait until the "offlining" CPU is back online and that may not happen forever. In particular, a system-wide deadlock may occur during CPU online as a result of that. The failing scenario is as follows. CPU0 is the boot CPU, so it creates a cpufreq policy and becomes the "leader" of it (policy->cpu). It cannot go offline, because it is the boot CPU. Next, other CPUs join the cpufreq policy as they go online and they leave it when they go offline. The last CPU to go offline, say CPU3, may queue up an IRQ work while running the governor callback on behalf of CPU0 after leaving the cpufreq policy because of the dvfs_possible_from_any_cpu effect described above. Then, CPU0 is the only online CPU in the system and the stale IRQ work is still queued on CPU3. When, say, CPU1 goes back online, it will run irq_work_sync() to wait for that IRQ work to complete and so it will wait for CPU3 to go back online (which may never happen even in principle), but (worse yet) CPU0 is waiting for CPU1 at that point too and a system-wide deadlock occurs. To address this problem notice that CPUs which cannot run cpufreq utilization update code for themselves (for example, because they have left the cpufreq policies that they belonged to), should also be prevented from running that code on behalf of the other CPUs that belong to a cpufreq policy with dvfs_possible_from_any_cpu set and so in that case the cpufreq_update_util_data pointer of the CPU running the code must not be NULL as well as for the CPU which is the target of the cpufreq utilization update in progress. Accordingly, change cpufreq_this_cpu_can_update() into a regular function in kernel/sched/cpufreq.c (instead of a static inline in a header file) and make it check the cpufreq_update_util_data pointer of the local CPU if dvfs_possible_from_any_cpu is set for the target cpufreq policy. Also update the schedutil governor to do the cpufreq_this_cpu_can_update() check in the non-fast-switch case too to avoid the stale IRQ work issues. Fixes: 99d14d0e16fa ("cpufreq: Process remote callbacks from any CPU if the platform permits") Link: https://lore.kernel.org/linux-pm/20191121093557.bycvdo4xyinbc5cb@vireshk-i7/ Reported-by: Anson Huang Tested-by: Anson Huang Cc: 4.14+ # 4.14+ Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Tested-by: Peng Fan (i.MX8QXP-MEK) Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

rfkill: allocate static minor

2019-12-31T15:35:38Z

[ Upstream commit 8670b2b8b029a6650d133486be9d2ace146fd29a ] udev has a feature of creating /dev/ device-nodes if it finds a devnode: modalias. This allows for auto-loading of modules that provide the node. This requires to use a statically allocated minor number for misc character devices. However, rfkill uses dynamic minor numbers and prevents auto-loading of the module. So allocate the next static misc minor number and use it for rfkill. Signed-off-by: Marcel Holtmann Link: https://lore.kernel.org/r/20191024174042.19851-1-marcel@holtmann.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

ipmi: Don't allow device module unload when in use

2019-12-31T15:35:23Z

[ Upstream commit cbb79863fc3175ed5ac506465948b02a893a8235 ] If something has the IPMI driver open, don't allow the device module to be unloaded. Before it would unload and the user would get errors on use. This change is made on user request, and it makes it consistent with the I2C driver, which has the same behavior. It does change things a little bit with respect to kernel users. If the ACPI or IPMI watchdog (or any other kernel user) has created a user, then the device module cannot be unloaded. Before it could be unloaded, This does not affect hot-plug. If the device goes away (it's on something removable that is removed or is hot-removed via sysfs) then it still behaves as it did before. Reported-by: tony camuso Signed-off-by: Corey Minyard Tested-by: tony camuso Signed-off-by: Sasha Levin

block: Fix writeback throttling W=1 compiler warnings

2019-12-31T15:34:59Z

[ Upstream commit 1d200e9d6f635ae894993a7d0f1b9e0b6e522e3b ] Fix the following compiler warnings: In file included from ./include/linux/bitmap.h:9, from ./include/linux/cpumask.h:12, from ./arch/x86/include/asm/cpumask.h:5, from ./arch/x86/include/asm/msr.h:11, from ./arch/x86/include/asm/processor.h:21, from ./arch/x86/include/asm/cpufeature.h:5, from ./arch/x86/include/asm/thread_info.h:53, from ./include/linux/thread_info.h:38, from ./arch/x86/include/asm/preempt.h:7, from ./include/linux/preempt.h:78, from ./include/linux/spinlock.h:51, from ./include/linux/mmzone.h:8, from ./include/linux/gfp.h:6, from ./include/linux/mm.h:10, from ./include/linux/bvec.h:13, from ./include/linux/blk_types.h:10, from block/blk-wbt.c:23: In function 'strncpy', inlined from 'perf_trace_wbt_stat' at ./include/trace/events/wbt.h:15:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'perf_trace_wbt_lat' at ./include/trace/events/wbt.h:58:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'perf_trace_wbt_step' at ./include/trace/events/wbt.h:87:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'perf_trace_wbt_timer' at ./include/trace/events/wbt.h:126:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'trace_event_raw_event_wbt_stat' at ./include/trace/events/wbt.h:15:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'trace_event_raw_event_wbt_lat' at ./include/trace/events/wbt.h:58:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'trace_event_raw_event_wbt_timer' at ./include/trace/events/wbt.h:126:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'trace_event_raw_event_wbt_step' at ./include/trace/events/wbt.h:87:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Cc: Christoph Hellwig Cc: Ming Lei Cc: Hannes Reinecke Cc: Johannes Thumshirn Fixes: e34cbd307477 ("blk-wbt: add general throttling mechanism"; v4.10). Signed-off-by: Bart Van Assche Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

media: cec-funcs.h: add status_req checks

2019-12-31T15:34:57Z

[ Upstream commit 9b211f9c5a0b67afc435b86f75d78273b97db1c5 ] The CEC_MSG_GIVE_DECK_STATUS and CEC_MSG_GIVE_TUNER_DEVICE_STATUS commands both have a status_req argument: ON, OFF, ONCE. If ON or ONCE, then the follower will reply with a STATUS message. Either once or whenever the status changes (status_req == ON). If status_req == OFF, then it will stop sending continuous status updates, but the follower will *not* send a STATUS message in that case. This means that if status_req == OFF, then msg->reply should be 0 as well since no reply is expected in that case. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin

drm: mst: Fix query_payload ack reply struct

2019-12-31T15:34:47Z

[ Upstream commit 268de6530aa18fe5773062367fd119f0045f6e88 ] Spec says[1] Allocated_PBN is 16 bits [1]- DisplayPort 1.2 Spec, Section 2.11.9.8, Table 2-98 Fixes: ad7f8a1f9ced ("drm/helper: add Displayport multi-stream helper (v0.6)") Cc: Lyude Paul Cc: Todd Previte Cc: Dave Airlie Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Sean Paul Cc: David Airlie Cc: Daniel Vetter Cc: dri-devel@lists.freedesktop.org Reviewed-by: Lyude Paul Signed-off-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20190829165223.129662-1-sean@poorly.run Signed-off-by: Sasha Levin

net: dst: Force 4-byte alignment of dst_metrics

2019-12-31T15:34:37Z

[ Upstream commit 258a980d1ec23e2c786e9536a7dd260bea74bae6 ] When storing a pointer to a dst_metrics structure in dst_entry._metrics, two flags are added in the least significant bits of the pointer value. Hence this assumes all pointers to dst_metrics structures have at least 4-byte alignment. However, on m68k, the minimum alignment of 32-bit values is 2 bytes, not 4 bytes. Hence in some kernel builds, dst_default_metrics may be only 2-byte aligned, leading to obscure boot warnings like: WARNING: CPU: 0 PID: 7 at lib/refcount.c:28 refcount_warn_saturate+0x44/0x9a refcount_t: underflow; use-after-free. Modules linked in: CPU: 0 PID: 7 Comm: ksoftirqd/0 Tainted: G W 5.5.0-rc2-atari-01448-g114a1a1038af891d-dirty #261 Stack from 10835e6c: 10835e6c 0038134f 00023fa6 00394b0f 0000001c 00000009 00321560 00023fea 00394b0f 0000001c 001a70f8 00000009 00000000 10835eb4 00000001 00000000 04208040 0000000a 00394b4a 10835ed4 00043aa8 001a70f8 00394b0f 0000001c 00000009 00394b4a 0026aba8 003215a4 00000003 00000000 0026d5a8 00000001 003215a4 003a4361 003238d6 000001f0 00000000 003215a4 10aa3b00 00025e84 003ddb00 10834000 002416a8 10aa3b00 00000000 00000080 000aa038 0004854a Call Trace: [<00023fa6>] __warn+0xb2/0xb4 [<00023fea>] warn_slowpath_fmt+0x42/0x64 [<001a70f8>] refcount_warn_saturate+0x44/0x9a [<00043aa8>] printk+0x0/0x18 [<001a70f8>] refcount_warn_saturate+0x44/0x9a [<0026aba8>] refcount_sub_and_test.constprop.73+0x38/0x3e [<0026d5a8>] ipv4_dst_destroy+0x5e/0x7e [<00025e84>] __local_bh_enable_ip+0x0/0x8e [<002416a8>] dst_destroy+0x40/0xae Fix this by forcing 4-byte alignment of all dst_metrics structures. Fixes: e5fd387ad5b30ca3 ("ipv6: do not overwrite inetpeer metrics prematurely") Signed-off-by: Geert Uytterhoeven Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

mod_devicetable: fix PHY module format

2019-12-31T15:34:36Z

[ Upstream commit d2ed49cf6c13e379c5819aa5ac20e1f9674ebc89 ] When a PHY is probed, if the top bit is set, we end up requesting a module with the string "mdio:-10101110000000100101000101010001" - the top bit is printed to a signed -1 value. This leads to the module not being loaded. Fix the module format string and the macro generating the values for it to ensure that we only print unsigned types and the top bit is always 0/1. We correctly end up with "mdio:10101110000000100101000101010001". Fixes: 8626d3b43280 ("phylib: Support phy module autoloading") Reviewed-by: Andrew Lunn Signed-off-by: Russell King Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: Protect accesses to .ts_recent_stamp with {READ,WRITE}_ONCE()

2019-12-21T09:57:19Z

[ Upstream commit 721c8dafad26ccfa90ff659ee19755e3377b829d ] Syncookies borrow the ->rx_opt.ts_recent_stamp field to store the timestamp of the last synflood. Protect them with READ_ONCE() and WRITE_ONCE() since reads and writes aren't serialised. Use of .rx_opt.ts_recent_stamp for storing the synflood timestamp was introduced by a0f82f64e269 ("syncookies: remove last_synq_overflow from struct tcp_sock"). But unprotected accesses were already there when timestamp was stored in .last_synq_overflow. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Guillaume Nault Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: tighten acceptance of ACKs not matching a child socket

2019-12-21T09:57:18Z

[ Upstream commit cb44a08f8647fd2e8db5cc9ac27cd8355fa392d8 ] When no synflood occurs, the synflood timestamp isn't updated. Therefore it can be so old that time_after32() can consider it to be in the future. That's a problem for tcp_synq_no_recent_overflow() as it may report that a recent overflow occurred while, in fact, it's just that jiffies has grown past 'last_overflow' + TCP_SYNCOOKIE_VALID + 2^31. Spurious detection of recent overflows lead to extra syncookie verification in cookie_v[46]_check(). At that point, the verification should fail and the packet dropped. But we should have dropped the packet earlier as we didn't even send a syncookie. Let's refine tcp_synq_no_recent_overflow() to report a recent overflow only if jiffies is within the [last_overflow, last_overflow + TCP_SYNCOOKIE_VALID] interval. This way, no spurious recent overflow is reported when jiffies wraps and 'last_overflow' becomes in the future from the point of view of time_after32(). However, if jiffies wraps and enters the [last_overflow, last_overflow + TCP_SYNCOOKIE_VALID] interval (with 'last_overflow' being a stale synflood timestamp), then tcp_synq_no_recent_overflow() still erroneously reports an overflow. In such cases, we have to rely on syncookie verification to drop the packet. We unfortunately have no way to differentiate between a fresh and a stale syncookie timestamp. In practice, using last_overflow as lower bound is problematic. If the synflood timestamp is concurrently updated between the time we read jiffies and the moment we store the timestamp in 'last_overflow', then 'now' becomes smaller than 'last_overflow' and tcp_synq_no_recent_overflow() returns true, potentially dropping a valid syncookie. Reading jiffies after loading the timestamp could fix the problem, but that'd require a memory barrier. Let's just accommodate for potential timestamp growth instead and extend the interval using 'last_overflow - HZ' as lower bound. Signed-off-by: Guillaume Nault Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman