Re: [PATCH v2 0/3] ipmi: Close the race between __scan_channels() and deliver_response()

[Corey Minyard <corey@minyard.net>]

On Fri, Dec 05, 2025 at 04:01:02PM +0800, Jinhui Guo wrote:
> On Fri, Oct 3, 2025 at 10:43:16AM -0500, Corey Minyard wrote:
> > On Tue, Sep 30, 2025 at 03:42:36PM +0800, Jinhui Guo wrote:
> > > The command "ipmi -b -t" would occasionally fail:
> > >   #ipmitool -b 6 -t 0x2c raw 0x6 0x01
> > >   Unable to send command: Invalid argument
> > >   Unable to send RAW command (channel=0x6 netfn=0x6 lun=0x0 cmd=0x1)
> > > 
> > > The race window between __scan_channels() and deliver_response() causes
> > > the parameters of some channels to be set to 0.
> > > 
> > > Fix the race between __scan_channels() and deliver_response() with the
> > > following changes.
> > > 
> > > 1. Only assign intf->channel_list = intf->wchannels and set
> > >    intf->channels_ready = true in channel_handler() after all channels_ready
> > >    have been successfully scanned or after failing to send the IPMI
> > >    request.
> > > 2. channel_handler() sets intf->channels_ready to true but no one clears
> > >    it, preventing __scan_channels() from rescanning channels. When the BMC
> > >    firmware changes a rescan is required. Allow it by clearing the flag
> > >    before starting a new scan.
> > > 3. Channels remain static unless the BMC firmware changes. Skip channel
> > >    rescan when no BMC firmware update has occurred.
> > > 
> > > 
> > > v1: https://lore.kernel.org/all/20250929081602.1901-1-guojinhui.liam@bytedance.com/
> > > 
> > > Changelog in v1 -> v2 (suggested by corey):
> > >  - Split the fix into three independent patches, each addressing a
> > >    separate issue.
> > >  - Clear intf->channels_ready only when the BMC firmware changes.
> > > 
> > > Jinhui Guo (3):
> > >   ipmi: Fix the race between __scan_channels() and deliver_response()
> > >   ipmi: Fix __scan_channels() failing to rescan channels
> > >   ipmi: Skip channel scan if channels are already marked ready
> 
> > I have these queued for 6.18.  I need to re-review them; that will
> > probably happen later in the cycle; I can't put them in until 6.17-rc1
> > releases.
> 
> > Thanks,
> 
> > -corey
> 
> Hi, corey
> 
> Friendly ping — please let me know if you need anything else (rebase, more review,
> test results) and I’ll be happy to take care of it.
> 
> Thanks for your time, and sorry for the noise.

No, it was a good reminder for me, I needed to handle this.

It's been sent to Linus.

Thanks,

-corey

> 
> Best regards,
> Jinhui
> 
> > > 
> > >  drivers/char/ipmi/ipmi_msghandler.c | 24 +++++++++++++++++-------
> > >  1 file changed, 17 insertions(+), 7 deletions(-)
> > > 
> > > -- 
> > > 2.20.1
> > >