* [tip: irq/urgent] PCI/MSI: Handle lack of irqdomain gracefully
2024-12-14 11:50 ` [Patch] PCI/MSI: Handle lack of irqdomain gracefully Thomas Gleixner
@ 2024-12-17 13:08 ` tip-bot2 for Thomas Gleixner
2025-02-03 19:16 ` [Patch] " patchwork-bot+linux-riscv
2026-03-11 11:22 ` Uwe Kleine-König
2 siblings, 0 replies; 7+ messages in thread
From: tip-bot2 for Thomas Gleixner @ 2024-12-17 13:08 UTC (permalink / raw)
To: linux-tip-commits
Cc: Alexandre Ghiti, Thomas Gleixner, stable, x86, linux-kernel, maz
The following commit has been merged into the irq/urgent branch of tip:
Commit-ID: a60b990798eb17433d0283788280422b1bd94b18
Gitweb: https://git.kernel.org/tip/a60b990798eb17433d0283788280422b1bd94b18
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Sat, 14 Dec 2024 12:50:18 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 16 Dec 2024 10:59:47 +01:00
PCI/MSI: Handle lack of irqdomain gracefully
Alexandre observed a warning emitted from pci_msi_setup_msi_irqs() on a
RISCV platform which does not provide PCI/MSI support:
WARNING: CPU: 1 PID: 1 at drivers/pci/msi/msi.h:121 pci_msi_setup_msi_irqs+0x2c/0x32
__pci_enable_msix_range+0x30c/0x596
pci_msi_setup_msi_irqs+0x2c/0x32
pci_alloc_irq_vectors_affinity+0xb8/0xe2
RISCV uses hierarchical interrupt domains and correctly does not implement
the legacy fallback. The warning triggers from the legacy fallback stub.
That warning is bogus as the PCI/MSI layer knows whether a PCI/MSI parent
domain is associated with the device or not. There is a check for MSI-X,
which has a legacy assumption. But that legacy fallback assumption is only
valid when legacy support is enabled, but otherwise the check should simply
return -ENOTSUPP.
Loongarch tripped over the same problem and blindly enabled legacy support
without implementing the legacy fallbacks. There are weak implementations
which return an error, so the problem was papered over.
Correct pci_msi_domain_supports() to evaluate the legacy mode and add
the missing supported check into the MSI enable path to complete it.
Fixes: d2a463b29741 ("PCI/MSI: Reject multi-MSI early")
Reported-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/87ed2a8ow5.ffs@tglx
---
drivers/pci/msi/irqdomain.c | 7 +++++--
drivers/pci/msi/msi.c | 4 ++++
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
index 5691257..d7ba879 100644
--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -350,8 +350,11 @@ bool pci_msi_domain_supports(struct pci_dev *pdev, unsigned int feature_mask,
domain = dev_get_msi_domain(&pdev->dev);
- if (!domain || !irq_domain_is_hierarchy(domain))
- return mode == ALLOW_LEGACY;
+ if (!domain || !irq_domain_is_hierarchy(domain)) {
+ if (IS_ENABLED(CONFIG_PCI_MSI_ARCH_FALLBACKS))
+ return mode == ALLOW_LEGACY;
+ return false;
+ }
if (!irq_domain_is_msi_parent(domain)) {
/*
diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 3a45879..2f647ca 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -433,6 +433,10 @@ int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
if (WARN_ON_ONCE(dev->msi_enabled))
return -EINVAL;
+ /* Test for the availability of MSI support */
+ if (!pci_msi_domain_supports(dev, 0, ALLOW_LEGACY))
+ return -ENOTSUPP;
+
nvec = pci_msi_vec_count(dev);
if (nvec < 0)
return nvec;
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [Patch] PCI/MSI: Handle lack of irqdomain gracefully
2024-12-14 11:50 ` [Patch] PCI/MSI: Handle lack of irqdomain gracefully Thomas Gleixner
2024-12-17 13:08 ` [tip: irq/urgent] " tip-bot2 for Thomas Gleixner
2025-02-03 19:16 ` [Patch] " patchwork-bot+linux-riscv
@ 2026-03-11 11:22 ` Uwe Kleine-König
2 siblings, 0 replies; 7+ messages in thread
From: Uwe Kleine-König @ 2026-03-11 11:22 UTC (permalink / raw)
To: Thomas Gleixner
Cc: Alexandre Ghiti, Paul Walmsley, Palmer Dabbelt, Anup Patel,
Sunil V L, linux-riscv, linux-kernel, Bjorn Helgaas, 1127635,
Aaron D. Johnson, regressions
[-- Attachment #1: Type: text/plain, Size: 12425 bytes --]
Control: forwarded -1 https://lore.kernel.org/lkml/abE_QoS5DM-ZltaV@monoceros
#regzbot introduced: a60b990798eb17433d0283788280422b1bd94b18
#regzbot from: "Aaron D. Johnson" <debbugreporter@fnord.greeley.co.us>
#regzbot monitor: https://bugs.debian.org/1127635
Hello,
On Sat, Dec 14, 2024 at 12:50:18PM +0100, Thomas Gleixner wrote:
> Alexandre observed a warning emitted from pci_msi_setup_msi_irqs() on a
> RISCV platform which does not provide PCI/MSI support:
>
> WARNING: CPU: 1 PID: 1 at drivers/pci/msi/msi.h:121 pci_msi_setup_msi_irqs+0x2c/0x32
> __pci_enable_msix_range+0x30c/0x596
> pci_msi_setup_msi_irqs+0x2c/0x32
> pci_alloc_irq_vectors_affinity+0xb8/0xe2
>
> RISCV uses hierarchical interrupt domains and correctly does not implement
> the legacy fallback. The warning triggers from the legacy fallback stub.
>
> That warning is bogus as the PCI/MSI layer knows whether a PCI/MSI parent
> domain is associated with the device or not. There is a check for MSI-X,
> which has a legacy assumption. But that legacy fallback assumption is only
> valid when legacy support is enabled, but otherwise the check should simply
> return -ENOTSUPP.
>
> Loongarch tripped over the same problem and blindly enabled legacy support
> without implementing the legacy fallbacks. There are weak implementations
> which return an error, so the problem was papered over.
>
> Correct pci_msi_domain_supports() to evaluate the legacy mode and add
> the missing supported check into the MSI enable path to complete it.
>
> Fixes: d2a463b29741 ("PCI/MSI: Reject multi-MSI early")
> Reported-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> Cc: stable@vger.kernel.org
this patch became a60b990798eb17433d0283788280422b1bd94b18 in v6.13-rc5
and was backported to 6.12.y and 6.6.y (aed157301c65 and b1f7476e07b9
respectively).
A Debian user (Aaron, on Cc:) on powerpc has boot problems and bisected
them to this commit. The relevant boot log of the failure is:
[ 2.643879] BUG: Kernel NULL pointer dereference on read at 0x00000000
[ 2.643891] Faulting instruction address: 0xc000000000a39514
[ 2.643902] Oops: Kernel access of bad area, sig: 11 [#1]
[ 2.643909] BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
[ 2.643920] Modules linked in: ohci_pci(+) ehci_hcd nvme_fabrics ohci_hcd nvme_keyring nvme_core usbcore nvme_auth scsi_transport_fc ipr configfs ehea(+) usb_common
[ 2.643965] CPU: 5 UID: 0 PID: 250 Comm: (udev-worker) Not tainted 6.12.17-powerpc64 #1 Debian 6.12.17-1
[ 2.643976] Hardware name: IBM,8204-E8A POWER6 (architected) 0x3e0302 0xf000002 of:IBM,EL350_118 hv:phyp pSeries
[ 2.643986] NIP: c000000000a39514 LR: c000000000a36ed8 CTR: c000000000a35820
[ 2.643995] REGS: c0000000351f6f60 TRAP: 0300 Not tainted (6.12.17-powerpc64 Debian 6.12.17-1)
[ 2.644004] MSR: 8000000000009032 <SF,EE,ME,IR,DR,RI> CR: 24222288 XER: 00000000
[ 2.644031] CFAR: c00000000000cfc4 DAR: 0000000000000000 DSISR: 40000000 IRQMASK: 0
[ 2.644031] GPR00: c000000000a36ed8 c0000000351f7200 c00000000182e200 c0000003df294000
[ 2.644031] GPR04: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 2.644031] GPR08: 0000000000000001 0000000000000000 c00000000228fcc0 0000000044222288
[ 2.644031] GPR12: c000000000a35820 c00000000eeacb00 0000000000000020 0000010037fcab20
[ 2.644031] GPR16: 0000000022222248 0000000000020000 0000000000000000 00003fffebe8bb80
[ 2.644031] GPR20: 0000000000000000 c00000000204db60 c00000000204dd60 c00000000b1ae780
[ 2.644031] GPR24: 0000000000000000 00003fff8c9ac758 0000000000000000 c0000003df294000
[ 2.644031] GPR28: 0000000000000001 0000000000000000 c0000003df294000 0000000000000001
[ 2.644164] NIP [c000000000a39514] pci_msi_domain_supports (drivers/pci/msi/irqdomain.c:366)
[ 2.644181] LR [c000000000a36ed8] __pci_enable_msi_range (drivers/pci/msi/msi.c:437)
[ 2.644192] Call Trace:
[ 2.644197] [c0000000351f7200] [c0000000351f7304] 0xc0000000351f7304 (unreliable)
[ 2.644211] [c0000000351f7340] [c000000000a3578c] pci_alloc_irq_vectors_affinity (drivers/pci/msi/api.c:277)
[ 2.644225] [c0000000351f73d0] [c0003d0007d2f4d4] usb_hcd_pci_probe (drivers/usb/core/hcd-pci.c:192) usbcore
[ 2.644246] [c0000000351f7470] [c0003d00084e6030] ohci_pci_probe (drivers/usb/host/ohci-pci.c:285) ohci_pci
[ 2.644260] [c0000000351f7490] [c000000000a260e8] local_pci_probe (drivers/pci/pci-driver.c:324)
[ 2.644274] [c0000000351f7510] [c000000000a26218] pci_call_probe (drivers/pci/pci-driver.c:392 (discriminator 1))
[ 2.644287] [c0000000351f7670] [c000000000a27348] pci_device_probe (drivers/pci/pci-driver.c:452)
[ 2.644300] [c0000000351f76b0] [c000000000b2e658] really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658)
[ 2.644314] [c0000000351f7740] [c000000000b2eb24] __driver_probe_device (drivers/base/dd.c:800)
[ 2.644327] [c0000000351f77c0] [c000000000b2edc4] driver_probe_device (drivers/base/dd.c:831)
[ 2.644340] [c0000000351f7800] [c000000000b2f188] __driver_attach (drivers/base/dd.c:1217)
[ 2.644352] [c0000000351f7880] [c000000000b2ac64] bus_for_each_dev (drivers/base/bus.c:370)
[ 2.644365] [c0000000351f78e0] [c000000000b2dac4] driver_attach (drivers/base/dd.c:1234)
[ 2.644377] [c0000000351f7900] [c000000000b2cd98] bus_add_driver (drivers/base/bus.c:675)
[ 2.644389] [c0000000351f7990] [c000000000b30ae4] driver_register (drivers/base/driver.c:246)
[ 2.644402] [c0000000351f7a00] [c000000000a24f88] __pci_register_driver (drivers/pci/pci-driver.c:1450)
[ 2.644415] [c0000000351f7a20] [c0003d00084e6800] ohci_pci_init (drivers/usb/host/ohci-pci.c:308) ohci_pci
[ 2.644429] [c0000000351f7a50] [c00000000000fd60] do_one_initcall (init/main.c:1269)
[ 2.644444] [c0000000351f7b30] [c0000000002760f8] do_init_module (kernel/module/main.c:2543)
[ 2.644460] [c0000000351f7bb0] [c000000000278fe4] init_module_from_file (kernel/module/main.c:3199)
[ 2.644473] [c0000000351f7c90] [c0000000002793e0] sys_finit_module (kernel/module/main.c:3211 kernel/module/main.c:3238 kernel/module/main.c:3221)
[ 2.644487] [c0000000351f7da0] [c00000000002c084] system_call_exception (arch/powerpc/kernel/syscall.c:171)
[ 2.644500] [c0000000351f7e50] [c00000000000cb54] system_call_common (arch/powerpc/kernel/interrupt_64.S:292)
[ 2.644515] --- interrupt: c00 at 0x3fff8d653d8c
[ 2.644522] NIP: 00003fff8d653d8c LR: 00003fff8c9a4680 CTR: 0000000000000000
[ 2.644531] REGS: c0000000351f7e80 TRAP: 0c00 Not tainted (6.12.17-powerpc64 Debian 6.12.17-1)
[ 2.644541] MSR: 800000000200f032 <SF,VEC,EE,PR,FP,ME,IR,DR,RI> CR: 22222222 XER: 00000000
[ 2.644573] IRQMASK: 0
[ 2.644573] GPR00: 0000000000000161 00003fffebe8b640 00003fff8d757100 0000000000000052
[ 2.644573] GPR04: 00003fff8c9ac758 0000000000000004 0000000000000058 000000000000005a
[ 2.644573] GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 2.644573] GPR12: 0000000000000000 00003fff8de947c0 0000000000000020 0000010037fcab20
[ 2.644573] GPR16: 0000000022222248 0000000000020000 0000000000000000 00003fffebe8bb80
[ 2.644573] GPR20: 0000000000000000 00003fffebe8bb70 0000000000000007 0000010037fca210
[ 2.644573] GPR24: 0000000000000000 0000000000000000 0000010037f6be40 0000000000000004
[ 2.644573] GPR28: 00003fff8c9ac758 0000000000020000 0000000000000004 0000010037fca210
[ 2.644698] NIP [00003fff8d653d8c] 0x3fff8d653d8c
[ 2.644705] LR [00003fff8c9a4680] 0x3fff8c9a4680
[ 2.644713] --- interrupt: c00
[ 2.644719] Code: 4182002c e92a0088 80690000 7c632038 7c632278 7c630034 5463d97e 786307e0 4e800020 60000000 60000000 e92a0020 <80690000> 4bffffd8 60000000 7ca50034
All code
========
0:* 41 82 00 2c beq 0x2c <-- trapping instruction
4: e9 2a 00 88 ld r9,136(r10)
8: 80 69 00 00 lwz r3,0(r9)
c: 7c 63 20 38 and r3,r3,r4
10: 7c 63 22 78 xor r3,r3,r4
14: 7c 63 00 34 cntlzw r3,r3
18: 54 63 d9 7e srwi r3,r3,5
1c: 78 63 07 e0 clrldi r3,r3,63
20: 4e 80 00 20 blr
24: 60 00 00 00 nop
28: 60 00 00 00 nop
2c: e9 2a 00 20 ld r9,32(r10)
30: 80 69 00 00 lwz r3,0(r9)
34: 4b ff ff d8 b 0xc
38: 60 00 00 00 nop
3c: 7c a5 00 34 cntlzw r5,r5
Code starting with the faulting instruction
===========================================
0: 80 69 00 00 lwz r3,0(r9)
4: 4b ff ff d8 b 0xffffffffffffffdc
8: 60 00 00 00 nop
c: 7c a5 00 34 cntlzw r5,r5
[ 2.644769] ---[ end trace 0000000000000000 ]---
(That's the bug splat from the bug report piped through
scripts/decode_stacktrace.sh)
The kernel has CONFIG_PCI_MSI_ARCH_FALLBACKS=y, so the first hunk
shouldn't change anything.
The disassembly of pci_msi_domain_supports in the kernel looks as
follows:
c000000000a394c0 <pci_msi_domain_supports>:
pci_msi_domain_supports():
debian/build/build_powerpc_none_powerpc64/drivers/pci/msi/irqdomain.c:334
c000000000a394c0: 60 00 00 00 nop
c000000000a394c4: 60 00 00 00 nop
debian/build/build_powerpc_none_powerpc64/drivers/pci/msi/irqdomain.c:353
c000000000a394c8: e9 43 02 e8 ld r10,744(r3)
c000000000a394cc: 2c 2a 00 00 cmpdi r10,0
c000000000a394d0: 41 82 00 50 beq c000000000a39520 <pci_msi_domain_supports+0x60>
irq_domain_is_hierarchy():
debian/build/build_powerpc_none_powerpc64/include/linux/irqdomain.h:661
c000000000a394d4: 81 2a 00 28 lwz r9,40(r10)
pci_msi_domain_supports():
debian/build/build_powerpc_none_powerpc64/drivers/pci/msi/irqdomain.c:353 (discriminator 1)
c000000000a394d8: 71 28 00 01 andi. r8,r9,1
c000000000a394dc: 41 82 00 44 beq c000000000a39520 <pci_msi_domain_supports+0x60>
debian/build/build_powerpc_none_powerpc64/drivers/pci/msi/irqdomain.c:359 (discriminator 1)
c000000000a394e0: 71 29 01 00 andi. r9,r9,256
c000000000a394e4: 41 82 00 2c beq c000000000a39510 <pci_msi_domain_supports+0x50>
debian/build/build_powerpc_none_powerpc64/drivers/pci/msi/irqdomain.c:375
c000000000a394e8: e9 2a 00 88 ld r9,136(r10)
c000000000a394ec: 80 69 00 00 lwz r3,0(r9)
debian/build/build_powerpc_none_powerpc64/drivers/pci/msi/irqdomain.c:378
c000000000a394f0: 7c 63 20 38 and r3,r3,r4
c000000000a394f4: 7c 63 22 78 xor r3,r3,r4
c000000000a394f8: 7c 63 00 34 cntlzw r3,r3
c000000000a394fc: 54 63 d9 7e srwi r3,r3,5
debian/build/build_powerpc_none_powerpc64/drivers/pci/msi/irqdomain.c:379
c000000000a39500: 78 63 07 e0 clrldi r3,r3,63
c000000000a39504: 4e 80 00 20 blr
c000000000a39508: 60 00 00 00 nop
c000000000a3950c: 60 00 00 00 nop
debian/build/build_powerpc_none_powerpc64/drivers/pci/msi/irqdomain.c:366
c000000000a39510: e9 2a 00 20 ld r9,32(r10)
c000000000a39514: 80 69 00 00 lwz r3,0(r9)
c000000000a39518: 4b ff ff d8 b c000000000a394f0 <pci_msi_domain_supports+0x30>
c000000000a3951c: 60 00 00 00 nop
debian/build/build_powerpc_none_powerpc64/drivers/pci/msi/irqdomain.c:355
c000000000a39520: 7c a5 00 34 cntlzw r5,r5
c000000000a39524: 54 a3 d9 7e srwi r3,r5,5
debian/build/build_powerpc_none_powerpc64/drivers/pci/msi/irqdomain.c:379
c000000000a39528: 78 63 07 e0 clrldi r3,r3,63
c000000000a3952c: 4e 80 00 20 blr
so the trapping happens in drivers/pci/msi/irqdomain.c:366 which is:
365 info = domain->host_data;
366 supported = info->flags;
According to the register dump domain == r10 == NULL, but then this code
would not have been reached and the faulting instruction would be at
c000000000a39510. So maybe it's only .host_data = NULL and the register
dump is unreliable??
The offsets match: .host_data is at offset 32 of struct
irq_domain and .flags is at offset 0 of struct msi_domain_info.
For more details see
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1127635 .
Does someone spot the issue?
Best regards
Uwe
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^ permalink raw reply [flat|nested] 7+ messages in thread