user/sven/linux.git/kernel, branch v4.19.176

fgraph: Initialize tracing_graph_pause at task creation

2021-02-13T12:51:13Z

commit 7e0a9220467dbcfdc5bc62825724f3e52e50ab31 upstream. On some archs, the idle task can call into cpu_suspend(). The cpu_suspend() will disable or pause function graph tracing, as there's some paths in bringing down the CPU that can have issues with its return address being modified. The task_struct structure has a "tracing_graph_pause" atomic counter, that when set to something other than zero, the function graph tracer will not modify the return address. The problem is that the tracing_graph_pause counter is initialized when the function graph tracer is enabled. This can corrupt the counter for the idle task if it is suspended in these architectures. CPU 1 CPU 2 ----- ----- do_idle() cpu_suspend() pause_graph_tracing() task_struct->tracing_graph_pause++ (0 -> 1) start_graph_tracing() for_each_online_cpu(cpu) { ftrace_graph_init_idle_task(cpu) task-struct->tracing_graph_pause = 0 (1 -> 0) unpause_graph_tracing() task_struct->tracing_graph_pause-- (0 -> -1) The above should have gone from 1 to zero, and enabled function graph tracing again. But instead, it is set to -1, which keeps it disabled. There's no reason that the field tracing_graph_pause on the task_struct can not be initialized at boot up. Cc: stable@vger.kernel.org Fixes: 380c4b1411ccd ("tracing/function-graph-tracer: append the tracing_graph_flag") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211339 Reported-by: pierre.gondois@arm.com Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

tracing/kprobe: Fix to support kretprobe events on unloaded modules

2021-02-13T12:51:13Z

commit 97c753e62e6c31a404183898d950d8c08d752dbd upstream. Fix kprobe_on_func_entry() returns error code instead of false so that register_kretprobe() can return an appropriate error code. append_trace_kprobe() expects the kprobe registration returns -ENOENT when the target symbol is not found, and it checks whether the target module is unloaded or not. If the target module doesn't exist, it defers to probe the target symbol until the module is loaded. However, since register_kretprobe() returns -EINVAL instead of -ENOENT in that case, it always fail on putting the kretprobe event on unloaded modules. e.g. Kprobe event: /sys/kernel/debug/tracing # echo p xfs:xfs_end_io >> kprobe_events [ 16.515574] trace_kprobe: This probe might be able to register after target module is loaded. Continue. Kretprobe event: (p -> r) /sys/kernel/debug/tracing # echo r xfs:xfs_end_io >> kprobe_events sh: write error: Invalid argument /sys/kernel/debug/tracing # cat error_log [ 41.122514] trace_kprobe: error: Failed to register probe event Command: r xfs:xfs_end_io ^ To fix this bug, change kprobe_on_func_entry() to detect symbol lookup failure and return -ENOENT in that case. Otherwise it returns -EINVAL or 0 (succeeded, given address is on the entry). Link: https://lkml.kernel.org/r/161176187132.1067016.8118042342894378981.stgit@devnote2 Cc: stable@vger.kernel.org Fixes: 59158ec4aef7 ("tracing/kprobes: Check the probe on unloaded module correctly") Reported-by: Jianlin Lv Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

genirq/msi: Activate Multi-MSI early when MSI_FLAG_ACTIVATE_EARLY is set

2021-02-10T08:21:07Z

commit 4c457e8cb75eda91906a4f89fc39bde3f9a43922 upstream. When MSI_FLAG_ACTIVATE_EARLY is set (which is the case for PCI), __msi_domain_alloc_irqs() performs the activation of the interrupt (which in the case of PCI results in the endpoint being programmed) as soon as the interrupt is allocated. But it appears that this is only done for the first vector, introducing an inconsistent behaviour for PCI Multi-MSI. Fix it by iterating over the number of vectors allocated to each MSI descriptor. This is easily achieved by introducing a new "for_each_msi_vector" iterator, together with a tiny bit of refactoring. Fixes: f3b0946d629c ("genirq/msi: Make sure PCI MSIs are activated early") Reported-by: Shameer Kolothum Signed-off-by: Marc Zyngier Signed-off-by: Thomas Gleixner Tested-by: Shameer Kolothum Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210123122759.1781359-1-maz@kernel.org Signed-off-by: Greg Kroah-Hartman

kretprobe: Avoid re-registration of the same kretprobe earlier

2021-02-10T08:21:07Z

commit 0188b87899ffc4a1d36a0badbe77d56c92fd91dc upstream. Our system encountered a re-init error when re-registering same kretprobe, where the kretprobe_instance in rp->free_instances is illegally accessed after re-init. Implementation to avoid re-registration has been introduced for kprobe before, but lags for register_kretprobe(). We must check if kprobe has been re-registered before re-initializing kretprobe, otherwise it will destroy the data struct of kretprobe registered, which can lead to memory leak, system crash, also some unexpected behaviors. We use check_kprobe_rereg() to check if kprobe has been re-registered before running register_kretprobe()'s body, for giving a warning message and terminate registration process. Link: https://lkml.kernel.org/r/20210128124427.2031088-1-bobo.shaobowang@huawei.com Cc: stable@vger.kernel.org Fixes: 1f0ab40976460 ("kprobes: Prevent re-registration of the same kprobe") [ The above commit should have been done for kretprobes too ] Acked-by: Naveen N. Rao Acked-by: Ananth N Mavinakayanahalli Acked-by: Masami Hiramatsu Signed-off-by: Wang ShaoBo Signed-off-by: Cheng Jian Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

elfcore: fix building with clang

2021-02-10T08:21:06Z

commit 6e7b64b9dd6d96537d816ea07ec26b7dedd397b9 upstream. kernel/elfcore.c only contains weak symbols, which triggers a bug with clang in combination with recordmcount: Cannot find symbol for section 2: .text. kernel/elfcore.o: failed Move the empty stubs into linux/elfcore.h as inline functions. As only two architectures use these, just use the architecture specific Kconfig symbols to key off the declaration. Link: https://lkml.kernel.org/r/20201204165742.3815221-2-arnd@kernel.org Signed-off-by: Arnd Bergmann Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Barret Rhoden Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

workqueue: Restrict affinity change to rescuer

2021-02-07T13:48:38Z

[ Upstream commit 640f17c82460e9724fd256f0a1f5d99e7ff0bda4 ] create_worker() will already set the right affinity using kthread_bind_mask(), this means only the rescuer will need to change it's affinity. Howveer, while in cpu-hot-unplug a regular task is not allowed to run on online&&!active as it would be pushed away quite agressively. We need KTHREAD_IS_PER_CPU to survive in that environment. Therefore set the affinity after getting that magic flag. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Tested-by: Valentin Schneider Link: https://lkml.kernel.org/r/20210121103506.826629830@infradead.org Signed-off-by: Sasha Levin

kthread: Extract KTHREAD_IS_PER_CPU

2021-02-07T13:48:38Z

[ Upstream commit ac687e6e8c26181a33270efd1a2e2241377924b0 ] There is a need to distinguish geniune per-cpu kthreads from kthreads that happen to have a single CPU affinity. Geniune per-cpu kthreads are kthreads that are CPU affine for correctness, these will obviously have PF_KTHREAD set, but must also have PF_NO_SETAFFINITY set, lest userspace modify their affinity and ruins things. However, these two things are not sufficient, PF_NO_SETAFFINITY is also set on other tasks that have their affinities controlled through other means, like for instance workqueues. Therefore another bit is needed; it turns out kthread_create_per_cpu() already has such a bit: KTHREAD_IS_PER_CPU, which is used to make kthread_park()/kthread_unpark() work correctly. Expose this flag and remove the implicit setting of it from kthread_create_on_cpu(); the io_uring usage of it seems dubious at best. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Tested-by: Valentin Schneider Link: https://lkml.kernel.org/r/20210121103506.557620262@infradead.org Signed-off-by: Sasha Levin

sysctl: handle overflow in proc_get_long

2021-02-07T13:48:37Z

commit 7f2923c4f73f21cfd714d12a2d48de8c21f11cfe upstream. proc_get_long() is a funny function. It uses simple_strtoul() and for a good reason. proc_get_long() wants to always succeed the parse and return the maybe incorrect value and the trailing characters to check against a pre-defined list of acceptable trailing values. However, simple_strtoul() explicitly ignores overflows which can cause funny things like the following to happen: echo 18446744073709551616 > /proc/sys/fs/file-max cat /proc/sys/fs/file-max 0 (Which will cause your system to silently die behind your back.) On the other hand kstrtoul() does do overflow detection but does not return the trailing characters, and also fails the parse when anything other than '\n' is a trailing character whereas proc_get_long() wants to be more lenient. Now, before adding another kstrtoul() function let's simply add a static parse strtoul_lenient() which: - fails on overflow with -ERANGE - returns the trailing characters to the caller The reason why we should fail on ERANGE is that we already do a partial fail on overflow right now. Namely, when the TMPBUFLEN is exceeded. So we already reject values such as 184467440737095516160 (21 chars) but accept values such as 18446744073709551616 (20 chars) but both are overflows. So we should just always reject 64bit overflows and not special-case this based on the number of chars. Link: http://lkml.kernel.org/r/20190107222700.15954-2-christian@brauner.io Signed-off-by: Christian Brauner Acked-by: Kees Cook Cc: "Eric W. Biederman" Cc: Luis Chamberlain Cc: Joe Lawrence Cc: Waiman Long Cc: Dominik Brodowski Cc: Al Viro Cc: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Joerg Vehlow Signed-off-by: Greg Kroah-Hartman

PM: hibernate: flush swap writer after marking

2021-02-03T22:23:24Z

commit fef9c8d28e28a808274a18fbd8cc2685817fd62a upstream. Flush the swap writer after, not before, marking the files, to ensure the signature is properly written. Fixes: 6f612af57821 ("PM / Hibernate: Group swap ops") Signed-off-by: Laurent Badel Cc: All applicable Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

kernel: kexec: remove the lock operation of system_transition_mutex

2021-02-03T22:23:23Z

commit 56c91a18432b631ca18438841fd1831ef756cabf upstream. Function kernel_kexec() is called with lock system_transition_mutex held in reboot system call. While inside kernel_kexec(), it will acquire system_transition_mutex agin. This will lead to dead lock. The dead lock should be easily triggered, it hasn't caused any failure report just because the feature 'kexec jump' is almost not used by anyone as far as I know. An inquiry can be made about who is using 'kexec jump' and where it's used. Before that, let's simply remove the lock operation inside CONFIG_KEXEC_JUMP ifdeffery scope. Fixes: 55f2503c3b69 ("PM / reboot: Eliminate race between reboot and suspend") Signed-off-by: Baoquan He Reported-by: Dan Carpenter Reviewed-by: Pingfan Liu Cc: 4.19+ # 4.19+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman