| Message ID | 7c3fece57a28462ae0c071c1cf72eb32541f1b91.1743074241.git.mykola_kvach@epam.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] xen/percpu: don't initialize percpu on resume | expand |
On Thu, Mar 27, 2025 at 1:32 PM Mykola Kvach <xakep.amatop@gmail.com> wrote: > Hmm, looks like this line... > From: Mykola Kvach <mykola_kvach@epam.com> ...shouldn't be here > > Invocation of the CPU_UP_PREPARE notification > on ARM64 during resume causes a crash: > > (XEN) [ 315.807606] Error bringing CPU1 up: -16 > (XEN) [ 315.811926] Xen BUG at common/cpu.c:258 > [...] > (XEN) [ 316.142765] Xen call trace: > (XEN) [ 316.146048] [<00000a0000202264>] enable_nonboot_cpus+0x128/0x1ac (PC) > (XEN) [ 316.153219] [<00000a000020225c>] enable_nonboot_cpus+0x120/0x1ac (LR) > (XEN) [ 316.160391] [<00000a0000278180>] suspend.c#system_suspend+0x4c/0x1a0 > (XEN) [ 316.167476] [<00000a0000206b70>] domain.c#continue_hypercall_tasklet_handler+0x54/0xd0 > (XEN) [ 316.176117] [<00000a0000226538>] tasklet.c#do_tasklet_work+0xb8/0x100 > (XEN) [ 316.183288] [<00000a0000226920>] do_tasklet+0x68/0xb0 > (XEN) [ 316.189077] [<00000a000026e120>] domain.c#idle_loop+0x7c/0x194 > (XEN) [ 316.195644] [<00000a0000277638>] shutdown.c#halt_this_cpu+0/0x14 > (XEN) [ 316.202383] [<0000000000000008>] 0000000000000008 > > Freeing per-CPU areas and setting __per_cpu_offset to INVALID_PERCPU_AREA > only occur when !park_offline_cpus and system_state is not SYS_STATE_suspend. > On ARM64, park_offline_cpus is always false, so setting __per_cpu_offset to > INVALID_PERCPU_AREA depends solely on the system state. > > If the system is suspended, this area is not freed, and during resume, an error > occurs in init_percpu_area, causing a crash because INVALID_PERCPU_AREA is not > set and park_offline_cpus remains 0: > > if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA ) > return park_offline_cpus ? 0 : -EBUSY; > > The same crash can occur on x86 if park_offline_cpus is set > to 0 during Xen resume. > > Fixes: f75780d26b2f ("xen: move per-cpu area management into common code") > Signed-off-by: Mykyta Poturai <mykyta_poturai@epam.com> > Signed-off-by: Mykola Kvach <mykola_kvach@epam.com> > Reviewed-by: Jan Beulich <jbeulich@suse.com> > --- > Changes introduced in V2: > - cosmetic fixes after review > - chnages in a commit message: add "Fixes" > --- > xen/common/percpu.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/xen/common/percpu.c b/xen/common/percpu.c > index e4e8b7bcab..b20f0460fc 100644 > --- a/xen/common/percpu.c > +++ b/xen/common/percpu.c > @@ -30,7 +30,9 @@ static int init_percpu_area(unsigned int cpu) > char *p; > > if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA ) > - return park_offline_cpus ? 0 : -EBUSY; > + return park_offline_cpus || system_state == SYS_STATE_resume > + ? 0 > + : -EBUSY; > > if ( (p = alloc_xenheap_pages(PERCPU_ORDER, 0)) == NULL ) > return -ENOMEM; > -- > 2.43.0 >
On 27.03.2025 12:37, Mykola Kvach wrote: > On Thu, Mar 27, 2025 at 1:32 PM Mykola Kvach <xakep.amatop@gmail.com> wrote: >> > > Hmm, looks like this line... > >> From: Mykola Kvach <mykola_kvach@epam.com> > > ...shouldn't be here And instead it should be "From: Mykyta Poturai <mykyta_poturai@epam.com>", to match ... >> Invocation of the CPU_UP_PREPARE notification >> on ARM64 during resume causes a crash: >> >> (XEN) [ 315.807606] Error bringing CPU1 up: -16 >> (XEN) [ 315.811926] Xen BUG at common/cpu.c:258 >> [...] >> (XEN) [ 316.142765] Xen call trace: >> (XEN) [ 316.146048] [<00000a0000202264>] enable_nonboot_cpus+0x128/0x1ac (PC) >> (XEN) [ 316.153219] [<00000a000020225c>] enable_nonboot_cpus+0x120/0x1ac (LR) >> (XEN) [ 316.160391] [<00000a0000278180>] suspend.c#system_suspend+0x4c/0x1a0 >> (XEN) [ 316.167476] [<00000a0000206b70>] domain.c#continue_hypercall_tasklet_handler+0x54/0xd0 >> (XEN) [ 316.176117] [<00000a0000226538>] tasklet.c#do_tasklet_work+0xb8/0x100 >> (XEN) [ 316.183288] [<00000a0000226920>] do_tasklet+0x68/0xb0 >> (XEN) [ 316.189077] [<00000a000026e120>] domain.c#idle_loop+0x7c/0x194 >> (XEN) [ 316.195644] [<00000a0000277638>] shutdown.c#halt_this_cpu+0/0x14 >> (XEN) [ 316.202383] [<0000000000000008>] 0000000000000008 >> >> Freeing per-CPU areas and setting __per_cpu_offset to INVALID_PERCPU_AREA >> only occur when !park_offline_cpus and system_state is not SYS_STATE_suspend. >> On ARM64, park_offline_cpus is always false, so setting __per_cpu_offset to >> INVALID_PERCPU_AREA depends solely on the system state. >> >> If the system is suspended, this area is not freed, and during resume, an error >> occurs in init_percpu_area, causing a crash because INVALID_PERCPU_AREA is not >> set and park_offline_cpus remains 0: >> >> if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA ) >> return park_offline_cpus ? 0 : -EBUSY; >> >> The same crash can occur on x86 if park_offline_cpus is set >> to 0 during Xen resume. >> >> Fixes: f75780d26b2f ("xen: move per-cpu area management into common code") >> Signed-off-by: Mykyta Poturai <mykyta_poturai@epam.com> ... the first S-o-b? >> Signed-off-by: Mykola Kvach <mykola_kvach@epam.com> >> Reviewed-by: Jan Beulich <jbeulich@suse.com> >> --- >> Changes introduced in V2: >> - cosmetic fixes after review >> - chnages in a commit message: add "Fixes" >> --- >> xen/common/percpu.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/xen/common/percpu.c b/xen/common/percpu.c >> index e4e8b7bcab..b20f0460fc 100644 >> --- a/xen/common/percpu.c >> +++ b/xen/common/percpu.c >> @@ -30,7 +30,9 @@ static int init_percpu_area(unsigned int cpu) >> char *p; >> >> if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA ) >> - return park_offline_cpus ? 0 : -EBUSY; >> + return park_offline_cpus || system_state == SYS_STATE_resume >> + ? 0 >> + : -EBUSY; Nit: That's not quite the indentation I suggested to use, I think? Jan
diff --git a/xen/common/percpu.c b/xen/common/percpu.c index e4e8b7bcab..b20f0460fc 100644 --- a/xen/common/percpu.c +++ b/xen/common/percpu.c @@ -30,7 +30,9 @@ static int init_percpu_area(unsigned int cpu) char *p; if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA ) - return park_offline_cpus ? 0 : -EBUSY; + return park_offline_cpus || system_state == SYS_STATE_resume + ? 0 + : -EBUSY; if ( (p = alloc_xenheap_pages(PERCPU_ORDER, 0)) == NULL ) return -ENOMEM;