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    SubjectRe: [PATCH V2 3/3] SH: cpuinfo: Fix a warning for CONFIG_CPUMASK_OFFSTACK
    Hi, SuperH maintainers,

    On Wed, Feb 8, 2023 at 8:59 PM John Paul Adrian Glaubitz
    <glaubitz@physik.fu-berlin.de> wrote:
    >
    > On Thu, 2022-07-14 at 16:41 +0800, Huacai Chen wrote:
    > > When CONFIG_CPUMASK_OFFSTACK and CONFIG_DEBUG_PER_CPU_MAPS is selected,
    > > cpu_max_bits_warn() generates a runtime warning similar as below while
    > > we show /proc/cpuinfo. Fix this by using nr_cpu_ids (the runtime limit)
    > > instead of NR_CPUS to iterate CPUs.
    > >
    > > [ 3.052463] ------------[ cut here ]------------
    > > [ 3.059679] WARNING: CPU: 3 PID: 1 at include/linux/cpumask.h:108 show_cpuinfo+0x5e8/0x5f0
    > > [ 3.070072] Modules linked in: efivarfs autofs4
    > > [ 3.076257] CPU: 0 PID: 1 Comm: systemd Not tainted 5.19-rc5+ #1052
    > > [ 3.099465] Stack : 9000000100157b08 9000000000f18530 9000000000cf846c 9000000100154000
    > > [ 3.109127] 9000000100157a50 0000000000000000 9000000100157a58 9000000000ef7430
    > > [ 3.118774] 90000001001578e8 0000000000000040 0000000000000020 ffffffffffffffff
    > > [ 3.128412] 0000000000aaaaaa 1ab25f00eec96a37 900000010021de80 900000000101c890
    > > [ 3.138056] 0000000000000000 0000000000000000 0000000000000000 0000000000aaaaaa
    > > [ 3.147711] ffff8000339dc220 0000000000000001 0000000006ab4000 0000000000000000
    > > [ 3.157364] 900000000101c998 0000000000000004 9000000000ef7430 0000000000000000
    > > [ 3.167012] 0000000000000009 000000000000006c 0000000000000000 0000000000000000
    > > [ 3.176641] 9000000000d3de08 9000000001639390 90000000002086d8 00007ffff0080286
    > > [ 3.186260] 00000000000000b0 0000000000000004 0000000000000000 0000000000071c1c
    > > [ 3.195868] ...
    > > [ 3.199917] Call Trace:
    > > [ 3.203941] [<90000000002086d8>] show_stack+0x38/0x14c
    > > [ 3.210666] [<9000000000cf846c>] dump_stack_lvl+0x60/0x88
    > > [ 3.217625] [<900000000023d268>] __warn+0xd0/0x100
    > > [ 3.223958] [<9000000000cf3c90>] warn_slowpath_fmt+0x7c/0xcc
    > > [ 3.231150] [<9000000000210220>] show_cpuinfo+0x5e8/0x5f0
    > > [ 3.238080] [<90000000004f578c>] seq_read_iter+0x354/0x4b4
    > > [ 3.245098] [<90000000004c2e90>] new_sync_read+0x17c/0x1c4
    > > [ 3.252114] [<90000000004c5174>] vfs_read+0x138/0x1d0
    > > [ 3.258694] [<90000000004c55f8>] ksys_read+0x70/0x100
    > > [ 3.265265] [<9000000000cfde9c>] do_syscall+0x7c/0x94
    > > [ 3.271820] [<9000000000202fe4>] handle_syscall+0xc4/0x160
    > > [ 3.281824] ---[ end trace 8b484262b4b8c24c ]---
    > >
    > > Cc: stable@vger.kernel.org
    > > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
    > > ---
    > > arch/sh/kernel/cpu/proc.c | 2 +-
    > > 1 file changed, 1 insertion(+), 1 deletion(-)
    > >
    > > diff --git a/arch/sh/kernel/cpu/proc.c b/arch/sh/kernel/cpu/proc.c
    > > index a306bcd6b341..5f6d0e827bae 100644
    > > --- a/arch/sh/kernel/cpu/proc.c
    > > +++ b/arch/sh/kernel/cpu/proc.c
    > > @@ -132,7 +132,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
    > >
    > > static void *c_start(struct seq_file *m, loff_t *pos)
    > > {
    > > - return *pos < NR_CPUS ? cpu_data + *pos : NULL;
    > > + return *pos < nr_cpu_ids ? cpu_data + *pos : NULL;
    > > }
    > > static void *c_next(struct seq_file *m, void *v, loff_t *pos)
    > > {
    >
    > I build-tested the patch and also booted the patched kernel successfully
    > on my SH-7785LCR board.
    >
    > Showing the contents of /proc/cpuinfo works fine, too:
    >
    > root@tirpitz:~> cat /proc/cpuinfo
    > machine : SH7785LCR
    > processor : 0
    > cpu family : sh4a
    > cpu type : SH7785
    > cut : 7.x
    > cpu flags : fpu perfctr llsc
    > cache type : split (harvard)
    > icache size : 32KiB (4-way)
    > dcache size : 32KiB (4-way)
    > address sizes : 32 bits physical
    > bogomips : 599.99
    > root@tirpitz:~>
    >
    > Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
    >
    > I am not sure yet whether the change is also correct as I don't know whether
    > it's possible to change the number of CPUs at runtime on SuperH.
    Can this patch be merged? This is the only one still unmerged in the
    whole series.

    Huacai

    >
    > Adrian
    >
    > --
    > .''`. John Paul Adrian Glaubitz
    > : :' : Debian Developer
    > `. `' Physicist
    > `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913

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