Re: [PATCH v2] padata: Put CPU offline callback in ONLINE section to allow failure

[Herbert Xu]

Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> wrote:
> syzbot reported the following warning:
> 
>    DEAD callback error for CPU1
>    WARNING: kernel/cpu.c:1463 at _cpu_down+0x759/0x1020 kernel/cpu.c:1463, CPU#0: syz.0.1960/14614
> 
> at commit 4ae12d8bd9a8 ("Merge tag 'kbuild-fixes-7.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux")
> which tglx traced to padata_cpu_dead() given it's the only
> sub-CPUHP_TEARDOWN_CPU callback that returns an error.
> 
> Failure isn't allowed in hotplug states before CPUHP_TEARDOWN_CPU
> so move the CPU offline callback to the ONLINE section where failure is
> possible.
> 
> Fixes: 894c9ef9780c ("padata: validate cpumask without removed CPU during offline")
> Reported-by: syzbot+123e1b70473ce213f3af@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://lore.kernel.org/all/69af0a05.050a0220.310d8.002f.GAE@xxxxxxxxxx/
> Debugged-by: Thomas Gleixner <tglx@xxxxxxxxxx>
> Signed-off-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
> ---
> 
> v2
> - Use non-atomic __cpumask_clear_cpu
> 
> Applies to cryptodev-2.6 but not mainline since it requires
>    https://lore.kernel.org/all/20260226080703.3157990-1-zhouchuyi@xxxxxxxxxxxxx/
> 
> include/linux/cpuhotplug.h |   1 -
> include/linux/padata.h     |   8 +--
> kernel/padata.c            | 120 +++++++++++++++++++------------------
> 3 files changed, 65 insertions(+), 64 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
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