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FAILED: patch "[PATCH] VMCI: fix race between vmci_host_setup_notify and" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 1bd6406fb5f36c2bb1e96e27d4c3e9f4d09edde4 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025061722-shaded-throwback-5dda@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 1bd6406fb5f36c2bb1e96e27d4c3e9f4d09edde4 Mon Sep 17 00:00:00 2001 From: Wupeng Ma <mawupeng1(a)huawei.com> Date: Sat, 10 May 2025 11:30:40 +0800 Subject: [PATCH] VMCI: fix race between vmci_host_setup_notify and vmci_ctx_unset_notify During our test, it is found that a warning can be trigger in try_grab_folio as follow: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1678 at mm/gup.c:147 try_grab_folio+0x106/0x130 Modules linked in: CPU: 0 UID: 0 PID: 1678 Comm: syz.3.31 Not tainted 6.15.0-rc5 #163 PREEMPT(undef) RIP: 0010:try_grab_folio+0x106/0x130 Call Trace: <TASK> follow_huge_pmd+0x240/0x8e0 follow_pmd_mask.constprop.0.isra.0+0x40b/0x5c0 follow_pud_mask.constprop.0.isra.0+0x14a/0x170 follow_page_mask+0x1c2/0x1f0 __get_user_pages+0x176/0x950 __gup_longterm_locked+0x15b/0x1060 ? gup_fast+0x120/0x1f0 gup_fast_fallback+0x17e/0x230 get_user_pages_fast+0x5f/0x80 vmci_host_unlocked_ioctl+0x21c/0xf80 RIP: 0033:0x54d2cd ---[ end trace 0000000000000000 ]--- Digging into the source, context->notify_page may init by get_user_pages_fast and can be seen in vmci_ctx_unset_notify which will try to put_page. However get_user_pages_fast is not finished here and lead to following try_grab_folio warning. The race condition is shown as follow: cpu0 cpu1 vmci_host_do_set_notify vmci_host_setup_notify get_user_pages_fast(uva, 1, FOLL_WRITE, &context->notify_page); lockless_pages_from_mm gup_pgd_range gup_huge_pmd // update &context->notify_page vmci_host_do_set_notify vmci_ctx_unset_notify notify_page = context->notify_page; if (notify_page) put_page(notify_page); // page is freed __gup_longterm_locked __get_user_pages follow_trans_huge_pmd try_grab_folio // warn here To slove this, use local variable page to make notify_page can be seen after finish get_user_pages_fast. Fixes: a1d88436d53a ("VMCI: Fix two UVA mapping bugs") Cc: stable <stable(a)kernel.org> Closes: https://lore.kernel.org/all/e91da589-ad57-3969-d979-879bbd10dddd@huawei.com/ Signed-off-by: Wupeng Ma <mawupeng1(a)huawei.com> Link: https://lore.kernel.org/r/20250510033040.901582-1-mawupeng1@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/misc/vmw_vmci/vmci_host.c b/drivers/misc/vmw_vmci/vmci_host.c index abe79f6fd2a7..b64944367ac5 100644 --- a/drivers/misc/vmw_vmci/vmci_host.c +++ b/drivers/misc/vmw_vmci/vmci_host.c @@ -227,6 +227,7 @@ static int drv_cp_harray_to_user(void __user *user_buf_uva, static int vmci_host_setup_notify(struct vmci_ctx *context, unsigned long uva) { + struct page *page; int retval; if (context->notify_page) { @@ -243,13 +244,11 @@ static int vmci_host_setup_notify(struct vmci_ctx *context, /* * Lock physical page backing a given user VA. */ - retval = get_user_pages_fast(uva, 1, FOLL_WRITE, &context->notify_page); - if (retval != 1) { - context->notify_page = NULL; + retval = get_user_pages_fast(uva, 1, FOLL_WRITE, &page); + if (retval != 1) return VMCI_ERROR_GENERIC; - } - if (context->notify_page == NULL) - return VMCI_ERROR_UNAVAILABLE; + + context->notify_page = page; /* * Map the locked page and set up notify pointer.

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FAILED: patch "[PATCH] usb: usbtmc: Fix read_stb function and get_stb ioctl" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x acb3dac2805d3342ded7dbbd164add32bbfdf21c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025061708-chaperone-fantasy-02f0@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From acb3dac2805d3342ded7dbbd164add32bbfdf21c Mon Sep 17 00:00:00 2001 From: Dave Penkler <dpenkler(a)gmail.com> Date: Wed, 21 May 2025 14:16:55 +0200 Subject: [PATCH] usb: usbtmc: Fix read_stb function and get_stb ioctl The usbtmc488_ioctl_read_stb function relied on a positive return from usbtmc_get_stb to reset the srq condition in the driver. The USBTMC_IOCTL_GET_STB case tested for a positive return to return the stb to the user. Commit: <cac01bd178d6> ("usb: usbtmc: Fix erroneous get_stb ioctl error returns") changed the return value of usbtmc_get_stb to 0 on success instead of returning the value of usb_control_msg which is positive in the normal case. This change caused the function usbtmc488_ioctl_read_stb and the USBTMC_IOCTL_GET_STB ioctl to no longer function correctly. Change the test in usbtmc488_ioctl_read_stb to test for failure first and return the failure code immediately. Change the test for the USBTMC_IOCTL_GET_STB ioctl to test for 0 instead of a positive value. Fixes: cac01bd178d6 ("usb: usbtmc: Fix erroneous get_stb ioctl error returns") Cc: stable(a)vger.kernel.org Signed-off-by: Dave Penkler <dpenkler(a)gmail.com> Link: https://lore.kernel.org/r/20250521121656.18174-3-dpenkler@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c index 740d2d2b19fb..08511442a27f 100644 --- a/drivers/usb/class/usbtmc.c +++ b/drivers/usb/class/usbtmc.c @@ -563,14 +563,15 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data, rv = usbtmc_get_stb(file_data, &stb); - if (rv > 0) { - srq_asserted = atomic_xchg(&file_data->srq_asserted, - srq_asserted); - if (srq_asserted) - stb |= 0x40; /* Set RQS bit */ + if (rv < 0) + return rv; + + srq_asserted = atomic_xchg(&file_data->srq_asserted, srq_asserted); + if (srq_asserted) + stb |= 0x40; /* Set RQS bit */ + + rv = put_user(stb, (__u8 __user *)arg); - rv = put_user(stb, (__u8 __user *)arg); - } return rv; } @@ -2199,7 +2200,7 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case USBTMC_IOCTL_GET_STB: retval = usbtmc_get_stb(file_data, &tmp_byte); - if (retval > 0) + if (!retval) retval = put_user(tmp_byte, (__u8 __user *)arg); break;

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FAILED: patch "[PATCH] usb: usbtmc: Fix read_stb function and get_stb ioctl" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x acb3dac2805d3342ded7dbbd164add32bbfdf21c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025061707-conceded-outwit-2f2f@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From acb3dac2805d3342ded7dbbd164add32bbfdf21c Mon Sep 17 00:00:00 2001 From: Dave Penkler <dpenkler(a)gmail.com> Date: Wed, 21 May 2025 14:16:55 +0200 Subject: [PATCH] usb: usbtmc: Fix read_stb function and get_stb ioctl The usbtmc488_ioctl_read_stb function relied on a positive return from usbtmc_get_stb to reset the srq condition in the driver. The USBTMC_IOCTL_GET_STB case tested for a positive return to return the stb to the user. Commit: <cac01bd178d6> ("usb: usbtmc: Fix erroneous get_stb ioctl error returns") changed the return value of usbtmc_get_stb to 0 on success instead of returning the value of usb_control_msg which is positive in the normal case. This change caused the function usbtmc488_ioctl_read_stb and the USBTMC_IOCTL_GET_STB ioctl to no longer function correctly. Change the test in usbtmc488_ioctl_read_stb to test for failure first and return the failure code immediately. Change the test for the USBTMC_IOCTL_GET_STB ioctl to test for 0 instead of a positive value. Fixes: cac01bd178d6 ("usb: usbtmc: Fix erroneous get_stb ioctl error returns") Cc: stable(a)vger.kernel.org Signed-off-by: Dave Penkler <dpenkler(a)gmail.com> Link: https://lore.kernel.org/r/20250521121656.18174-3-dpenkler@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c index 740d2d2b19fb..08511442a27f 100644 --- a/drivers/usb/class/usbtmc.c +++ b/drivers/usb/class/usbtmc.c @@ -563,14 +563,15 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data, rv = usbtmc_get_stb(file_data, &stb); - if (rv > 0) { - srq_asserted = atomic_xchg(&file_data->srq_asserted, - srq_asserted); - if (srq_asserted) - stb |= 0x40; /* Set RQS bit */ + if (rv < 0) + return rv; + + srq_asserted = atomic_xchg(&file_data->srq_asserted, srq_asserted); + if (srq_asserted) + stb |= 0x40; /* Set RQS bit */ + + rv = put_user(stb, (__u8 __user *)arg); - rv = put_user(stb, (__u8 __user *)arg); - } return rv; } @@ -2199,7 +2200,7 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case USBTMC_IOCTL_GET_STB: retval = usbtmc_get_stb(file_data, &tmp_byte); - if (retval > 0) + if (!retval) retval = put_user(tmp_byte, (__u8 __user *)arg); break;

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Backports of d0afcfeb9e3810ec89d1ffde1a0e36621bb75dca for 6.6 and older

by Nathan Chancellor

Hi Greg and Sasha, Please find attached backports of commit d0afcfeb9e38 ("kbuild: Disable -Wdefault-const-init-unsafe") for 6.6 and older, which is needed for tip of tree versions of LLVM. Please let me know if there are any questions. Cheers, Nathan

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Re: Patch "net: sch_ets: Add a new Qdisc" has been added to the 5.4-stable tree

by Petr Machata

Sasha Levin <sashal(a)kernel.org> writes: > This is a note to let you know that I've just added the patch titled > > net: sch_ets: Add a new Qdisc > > to the 5.4-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… > > The filename of the patch is: > net-sch_ets-add-a-new-qdisc.patch > and it can be found in the queue-5.4 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable(a)vger.kernel.org> know about it. Not sure what the motivation is to include a pure added feature to a stable tree. But if you truly want the patch, then there were a couple follow up fixes over the years. At least the following look like patches to code that would be problematic in 5.4.y as well: cd9b50adc6bb ("net/sched: ets: fix crash when flipping from 'strict' to 'quantum'") 454d3e1ae057 ("net/sched: sch_ets: properly init all active DRR list handles") de6d25924c2a ("net/sched: sch_ets: don't peek at classes beyond 'nbands'") c062f2a0b04d ("net/sched: sch_ets: don't remove idle classes from the round-robin list") d62b04fca434 ("net: sched: fix ets qdisc OOB Indexing") 1a6d0c00fa07 ("net_sched: ets: Fix double list add in class with netem as child qdisc")

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Re: Patch "powerpc: do not build ppc_save_regs.o always" has been added to the 6.15-stable tree

by Jiri Slaby

On 10. 06. 25, 13:56, Sasha Levin wrote: > This is a note to let you know that I've just added the patch titled > > powerpc: do not build ppc_save_regs.o always > > to the 6.15-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… Please drop this from all trees. It was correctly broken. The whole if was removed later by 93bd4a80efeb521314485a06d8c21157240497bb. > The filename of the patch is: > powerpc-do-not-build-ppc_save_regs.o-always.patch > and it can be found in the queue-6.15 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable(a)vger.kernel.org> know about it. > > > > commit 242c2ba3f16d92cd81c309725550f6c723833ae3 > Author: Jiri Slaby (SUSE) <jirislaby(a)kernel.org> > Date: Thu Apr 17 12:53:05 2025 +0200 > > powerpc: do not build ppc_save_regs.o always > > [ Upstream commit 497b7794aef03d525a5be05ae78dd7137c6861a5 ] > > The Fixes commit below tried to add CONFIG_PPC_BOOK3S to one of the > conditions to enable the build of ppc_save_regs.o. But it failed to do > so, in fact. The commit omitted to add a dollar sign. > > Therefore, ppc_save_regs.o is built always these days (as > "(CONFIG_PPC_BOOK3S)" is never an empty string). > > Fix this by adding the missing dollar sign. > > Signed-off-by: Jiri Slaby (SUSE) <jirislaby(a)kernel.org> > Fixes: fc2a5a6161a2 ("powerpc/64s: ppc_save_regs is now needed for all 64s builds") > Acked-by: Stephen Rothwell <sfr(a)canb.auug.org.au> > Signed-off-by: Madhavan Srinivasan <maddy(a)linux.ibm.com> > Link: https://patch.msgid.link/20250417105305.397128-1-jirislaby@kernel.org > Signed-off-by: Sasha Levin <sashal(a)kernel.org> > > diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile > index 6ac621155ec3c..0c26b2412d173 100644 > --- a/arch/powerpc/kernel/Makefile > +++ b/arch/powerpc/kernel/Makefile > @@ -160,7 +160,7 @@ endif > > obj64-$(CONFIG_PPC_TRANSACTIONAL_MEM) += tm.o > > -ifneq ($(CONFIG_XMON)$(CONFIG_KEXEC_CORE)(CONFIG_PPC_BOOK3S),) > +ifneq ($(CONFIG_XMON)$(CONFIG_KEXEC_CORE)$(CONFIG_PPC_BOOK3S),) > obj-y += ppc_save_regs.o > endif > -- js suse labs

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RE: Patch "Drivers: hv: Always select CONFIG_SYSFB for Hyper-V guests" has been added to the 6.15-stable tree

by Michael Kelley

From: Sasha Levin <sashal(a)kernel.org> > > This is a note to let you know that I've just added the patch titled > > Drivers: hv: Always select CONFIG_SYSFB for Hyper-V guests > > to the 6.15-stable tree which can be found at: > > https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git > > The filename of the patch is: > drivers-hv-always-select-config_sysfb-for-hyper-v-gu.patch > and it can be found in the queue-6.15 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable(a)vger.kernel.org> know about it. Please DO NOT backport this patch to ANY stable trees, at least not at the moment. It is causing a config problem that we're trying to work out. Once the resolution is decided upon, we can figure out what to backport. Thanks, Michael Kelley > > > > commit 9766859ee9884c35dde0411df167a06452fee3ce > Author: Michael Kelley <mhklinux(a)outlook.com> > Date: Mon May 19 21:01:43 2025 -0700 > > Drivers: hv: Always select CONFIG_SYSFB for Hyper-V guests > > [ Upstream commit 96959283a58d91ae20d025546f00e16f0a555208 ] > > The Hyper-V host provides guest VMs with a range of MMIO addresses > that guest VMBus drivers can use. The VMBus driver in Linux manages > that MMIO space, and allocates portions to drivers upon request. As > part of managing that MMIO space in a Generation 2 VM, the VMBus > driver must reserve the portion of the MMIO space that Hyper-V has > designated for the synthetic frame buffer, and not allocate this > space to VMBus drivers other than graphics framebuffer drivers. The > synthetic frame buffer MMIO area is described by the screen_info data > structure that is passed to the Linux kernel at boot time, so the > VMBus driver must access screen_info for Generation 2 VMs. (In > Generation 1 VMs, the framebuffer MMIO space is communicated to > the guest via a PCI pseudo-device, and access to screen_info is > not needed.) > > In commit a07b50d80ab6 ("hyperv: avoid dependency on screen_info") > the VMBus driver's access to screen_info is restricted to when > CONFIG_SYSFB is enabled. CONFIG_SYSFB is typically enabled in kernels > built for Hyper-V by virtue of having at least one of CONFIG_FB_EFI, > CONFIG_FB_VESA, or CONFIG_SYSFB_SIMPLEFB enabled, so the restriction > doesn't usually affect anything. But it's valid to have none of these > enabled, in which case CONFIG_SYSFB is not enabled, and the VMBus driver > is unable to properly reserve the framebuffer MMIO space for graphics > framebuffer drivers. The framebuffer MMIO space may be assigned to > some other VMBus driver, with undefined results. As an example, if > a VM is using a PCI pass-thru NVMe controller to host the OS disk, > the PCI NVMe controller is probed before any graphics devices, and the > NVMe controller is assigned a portion of the framebuffer MMIO space. > Hyper-V reports an error to Linux during the probe, and the OS disk > fails to get setup. Then Linux fails to boot in the VM. > > Fix this by having CONFIG_HYPERV always select SYSFB. Then the > VMBus driver in a Gen 2 VM can always reserve the MMIO space for the > graphics framebuffer driver, and prevent the undefined behavior. But > don't select SYSFB when building for HYPERV_VTL_MODE as VTLs other > than VTL 0 don't have a framebuffer and aren't subject to the issue. > Adding SYSFB in such cases is harmless, but would increase the image > size for no purpose. > > Fixes: a07b50d80ab6 ("hyperv: avoid dependency on screen_info") > Signed-off-by: Michael Kelley <mhklinux(a)outlook.com> > Reviewed-by: Saurabh Sengar <ssengar(a)linux.microsoft.com> > Link: > https://lore.kernel.org/st > able%2F20250520040143.6964-1- > mhklinux%2540outlook.com&data=05%7C02%7C%7C516ef64661c145eb315d08dda81861 > 51%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638851544842065319%7CUn > known%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXa > W4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=FZnrM9REMICWp > JqW88gD7CxeTwcztS2y8%2B8GqHNtF3E%3D&reserved=0 > Link: > https://lore.kernel.org/r%25 > 2F20250520040143.6964-1- > mhklinux%40outlook.com&data=05%7C02%7C%7C516ef64661c145eb315d08dda8186151 > %7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638851544842081386%7CUnkn > own%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4 > zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=j%2F5AvOlxwTKfVUL > vmNr%2FZliwRVrd9rSlVECyFGqFErE%3D&reserved=0 > Signed-off-by: Wei Liu <wei.liu(a)kernel.org> > Message-ID: <20250520040143.6964-1-mhklinux(a)outlook.com> > Signed-off-by: Sasha Levin <sashal(a)kernel.org> > > diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig > index 6c1416167bd2e..724fc08a73e70 100644 > --- a/drivers/hv/Kconfig > +++ b/drivers/hv/Kconfig > @@ -9,6 +9,7 @@ config HYPERV > select PARAVIRT > select X86_HV_CALLBACK_VECTOR if X86 > select OF_EARLY_FLATTREE if OF > + select SYSFB if !HYPERV_VTL_MODE > help > Select this option to run Linux as a Hyper-V client operating > system.

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6.6-stable inclusion request

by Jens Axboe

Hi, Can you add these three patches to 6.6-stable? It fixes a behavioral change with 6.6-stable that Rom reported, affecting OpenBMC. Other stable versions not affected, as they got the required fixes on top backported already. Thanks, -- Jens Axboe

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[PATCH AUTOSEL 5.4 1/5] ALSA: hda: Ignore unsol events for cards being shut down

by Sasha Levin

From: Cezary Rojewski <cezary.rojewski(a)intel.com> [ Upstream commit 3f100f524e75586537e337b34d18c8d604b398e7 ] For the classic snd_hda_intel driver, codec->card and bus->card point to the exact same thing. When snd_card_diconnect() fires, bus->shutdown is set thanks to azx_dev_disconnect(). card->shutdown is already set when that happens but both provide basically the same functionality. For the DSP snd_soc_avs driver where multiple codecs are located on multiple cards, bus->shutdown 'shortcut' is not sufficient. One codec card may be unregistered while other codecs are still operational. Proper check in form of card->shutdown must be used to verify whether the codec's card is being shut down. Reviewed-by: Amadeusz Sławiński <amadeuszx.slawinski(a)linux.intel.com> Signed-off-by: Cezary Rojewski <cezary.rojewski(a)intel.com> Link: https://patch.msgid.link/20250530141309.2943404-1-cezary.rojewski@intel.com Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- **YES** This commit should be backported to stable kernel trees. Here's my extensive analysis: ## Technical Analysis ### Core Problem Being Fixed The commit addresses a **shutdown race condition** in multi-codec HDA systems, specifically in DSP/AVS drivers where multiple HDA codecs exist on the same sound card but with separate bus instances. The change modifies line 47 in `sound/pci/hda/hda_bind.c`: **Before:** ```c if (codec->bus->shutdown) return; ``` **After:** ```c if (codec->card->shutdown || codec->bus->shutdown) return; ``` ### Why This is a Good Backport Candidate **1. Bug Fix Nature - Small and Contained** - This is a clear **bug fix** addressing a specific shutdown race condition - The change is **minimal** (adding one condition check) and **well- contained** - No architectural changes or new features introduced - Low risk of introducing regressions **2. Critical Subsystem Impact** - Affects **HD-audio subsystem** which is critical for audio functionality - Could prevent system crashes or hangs during shutdown in multi-codec scenarios - Improves system stability during shutdown sequences **3. Technical Correctness** The fix addresses a **fundamental timing issue**: - In multi-codec systems, `card->shutdown` is set at the ALSA core level during `snd_card_disconnect()` - `bus->shutdown` is set later at the HDA controller level during individual codec shutdown - **Gap exists** where unsol events could be processed after card shutdown but before bus shutdown - This can cause codec operations on an already-disconnected sound card **4. Follows Stable Tree Criteria** - **Important bug fix**: Prevents potential system instability during shutdown - **Minimal risk**: Only adds an additional safety check, doesn't change existing logic - **Well-understood**: The change is straightforward and follows existing patterns seen in similar commits - **Confined to subsystem**: Only affects HDA audio subsystem **5. Consistency with Similar Backported Commits** This follows the exact same pattern as the historical commits that were successfully backported: - **Similar Commit #1**: Added `bus->shutdown` check to prevent unsol events during shutdown - **Backported (YES)** - **Similar Commit #2**: Added suspend/resume state check to unsol handler - **Backported (YES)** - **Similar Commit #3**: Added jack disconnection during codec unbind - **Backported (YES)** - **Similar Commit #4**: Added bus_probing flag to serialize codec registration - **Backported (YES)** All these commits follow the same pattern: **small, targeted fixes to prevent race conditions in HDA shutdown/initialization sequences**. **6. Real-World Impact** - Affects **DSP/AVS audio systems** which are increasingly common in modern hardware - Without this fix, systems with multiple audio codecs could experience: - Kernel oops during shutdown - System hangs - Audio subsystem corruption - Unpredictable behavior during reboot sequences ### Risk Assessment **Very Low Risk:** - The change only **adds** a safety check, doesn't remove existing functionality - `card->shutdown` check is used extensively throughout the ALSA subsystem already - Maintains **backward compatibility** completely - If `card->shutdown` is false, behavior is identical to before - No changes to data structures, APIs, or functional logic ### Conclusion This commit represents a **textbook stable backport candidate**: it's a small, well-understood bug fix that addresses a real stability issue in a critical subsystem with minimal risk of regression. The pattern matches multiple previously successful backports in the same subsystem, and the technical merit is clear. sound/pci/hda/hda_bind.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/pci/hda/hda_bind.c b/sound/pci/hda/hda_bind.c index 17a25e453f60c..047fe6cca7f1a 100644 --- a/sound/pci/hda/hda_bind.c +++ b/sound/pci/hda/hda_bind.c @@ -44,7 +44,7 @@ static void hda_codec_unsol_event(struct hdac_device *dev, unsigned int ev) struct hda_codec *codec = container_of(dev, struct hda_codec, core); /* ignore unsol events during shutdown */ - if (codec->bus->shutdown) + if (codec->card->shutdown || codec->bus->shutdown) return; /* ignore unsol events during system suspend/resume */ -- 2.39.5

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[PATCH AUTOSEL 5.10 1/6] ALSA: hda: Ignore unsol events for cards being shut down

by Sasha Levin

From: Cezary Rojewski <cezary.rojewski(a)intel.com> [ Upstream commit 3f100f524e75586537e337b34d18c8d604b398e7 ] For the classic snd_hda_intel driver, codec->card and bus->card point to the exact same thing. When snd_card_diconnect() fires, bus->shutdown is set thanks to azx_dev_disconnect(). card->shutdown is already set when that happens but both provide basically the same functionality. For the DSP snd_soc_avs driver where multiple codecs are located on multiple cards, bus->shutdown 'shortcut' is not sufficient. One codec card may be unregistered while other codecs are still operational. Proper check in form of card->shutdown must be used to verify whether the codec's card is being shut down. Reviewed-by: Amadeusz Sławiński <amadeuszx.slawinski(a)linux.intel.com> Signed-off-by: Cezary Rojewski <cezary.rojewski(a)intel.com> Link: https://patch.msgid.link/20250530141309.2943404-1-cezary.rojewski@intel.com Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- **YES** This commit should be backported to stable kernel trees. Here's my extensive analysis: ## Technical Analysis ### Core Problem Being Fixed The commit addresses a **shutdown race condition** in multi-codec HDA systems, specifically in DSP/AVS drivers where multiple HDA codecs exist on the same sound card but with separate bus instances. The change modifies line 47 in `sound/pci/hda/hda_bind.c`: **Before:** ```c if (codec->bus->shutdown) return; ``` **After:** ```c if (codec->card->shutdown || codec->bus->shutdown) return; ``` ### Why This is a Good Backport Candidate **1. Bug Fix Nature - Small and Contained** - This is a clear **bug fix** addressing a specific shutdown race condition - The change is **minimal** (adding one condition check) and **well- contained** - No architectural changes or new features introduced - Low risk of introducing regressions **2. Critical Subsystem Impact** - Affects **HD-audio subsystem** which is critical for audio functionality - Could prevent system crashes or hangs during shutdown in multi-codec scenarios - Improves system stability during shutdown sequences **3. Technical Correctness** The fix addresses a **fundamental timing issue**: - In multi-codec systems, `card->shutdown` is set at the ALSA core level during `snd_card_disconnect()` - `bus->shutdown` is set later at the HDA controller level during individual codec shutdown - **Gap exists** where unsol events could be processed after card shutdown but before bus shutdown - This can cause codec operations on an already-disconnected sound card **4. Follows Stable Tree Criteria** - **Important bug fix**: Prevents potential system instability during shutdown - **Minimal risk**: Only adds an additional safety check, doesn't change existing logic - **Well-understood**: The change is straightforward and follows existing patterns seen in similar commits - **Confined to subsystem**: Only affects HDA audio subsystem **5. Consistency with Similar Backported Commits** This follows the exact same pattern as the historical commits that were successfully backported: - **Similar Commit #1**: Added `bus->shutdown` check to prevent unsol events during shutdown - **Backported (YES)** - **Similar Commit #2**: Added suspend/resume state check to unsol handler - **Backported (YES)** - **Similar Commit #3**: Added jack disconnection during codec unbind - **Backported (YES)** - **Similar Commit #4**: Added bus_probing flag to serialize codec registration - **Backported (YES)** All these commits follow the same pattern: **small, targeted fixes to prevent race conditions in HDA shutdown/initialization sequences**. **6. Real-World Impact** - Affects **DSP/AVS audio systems** which are increasingly common in modern hardware - Without this fix, systems with multiple audio codecs could experience: - Kernel oops during shutdown - System hangs - Audio subsystem corruption - Unpredictable behavior during reboot sequences ### Risk Assessment **Very Low Risk:** - The change only **adds** a safety check, doesn't remove existing functionality - `card->shutdown` check is used extensively throughout the ALSA subsystem already - Maintains **backward compatibility** completely - If `card->shutdown` is false, behavior is identical to before - No changes to data structures, APIs, or functional logic ### Conclusion This commit represents a **textbook stable backport candidate**: it's a small, well-understood bug fix that addresses a real stability issue in a critical subsystem with minimal risk of regression. The pattern matches multiple previously successful backports in the same subsystem, and the technical merit is clear. sound/pci/hda/hda_bind.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/pci/hda/hda_bind.c b/sound/pci/hda/hda_bind.c index 0a83afa5f373c..6625643f333e8 100644 --- a/sound/pci/hda/hda_bind.c +++ b/sound/pci/hda/hda_bind.c @@ -44,7 +44,7 @@ static void hda_codec_unsol_event(struct hdac_device *dev, unsigned int ev) struct hda_codec *codec = container_of(dev, struct hda_codec, core); /* ignore unsol events during shutdown */ - if (codec->bus->shutdown) + if (codec->card->shutdown || codec->bus->shutdown) return; /* ignore unsol events during system suspend/resume */ -- 2.39.5

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