e9445a7a59
[ Upstream commit de2ae403b4c0e79a3410e63bc448542fbb9f9bfc ] is_xen_pmu() is taking the cpu number as parameter, but it is not using it. Instead it just tests whether the Xen PMU initialization on the current cpu did succeed. As this test is done by checking a percpu pointer, preemption needs to be disabled in order to avoid switching the cpu while doing the test. While resuming from suspend() this seems not to be the case: [ 88.082751] ACPI: PM: Low-level resume complete [ 88.087933] ACPI: EC: EC started [ 88.091464] ACPI: PM: Restoring platform NVS memory [ 88.097166] xen_acpi_processor: Uploading Xen processor PM info [ 88.103850] Enabling non-boot CPUs ... [ 88.108128] installing Xen timer for CPU 1 [ 88.112763] BUG: using smp_processor_id() in preemptible [00000000] code: systemd-sleep/7138 [ 88.122256] caller is is_xen_pmu+0x12/0x30 [ 88.126937] CPU: 0 PID: 7138 Comm: systemd-sleep Tainted: G W 5.16.13-2.fc32.qubes.x86_64 #1 [ 88.137939] Hardware name: Star Labs StarBook/StarBook, BIOS 7.97 03/21/2022 [ 88.145930] Call Trace: [ 88.148757] <TASK> [ 88.151193] dump_stack_lvl+0x48/0x5e [ 88.155381] check_preemption_disabled+0xde/0xe0 [ 88.160641] is_xen_pmu+0x12/0x30 [ 88.164441] xen_smp_intr_init_pv+0x75/0x100 Fix that by replacing is_xen_pmu() by a simple boolean variable which reflects the Xen PMU initialization state on cpu 0. Modify xen_pmu_init() to return early in case it is being called for a cpu other than cpu 0 and the boolean variable not being set. Fixes: bf6dfb154d93 ("xen/PMU: PMU emulation code") Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20220325142002.31789-1-jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.