The branch main has been updated by jhibbits:
URL:
https://cgit.FreeBSD.org/src/commit/?id=80ec95226e170d36071b0542ade8fbcf417e7aa5
commit 80ec95226e170d36071b0542ade8fbcf417e7aa5
Author: Shawn Anastasio <sanasta...@raptorengineering.com>
AuthorDate: 2025-02-09 17:27:07 +0000
Commit: Justin Hibbits <jhibb...@freebsd.org>
CommitDate: 2025-02-09 17:29:56 +0000
busdma: Always initialize bounce page STAILQ
Summary:
Always call STAILQ_INIT in bus_dmamap_create regardless of whether
BUS_DMA_COULD_BOUNCE is set. This avoids tripping the assertions added
by commit 34740937f7a4 when the queue is checked with STAILQ_EMPTY in
free_bounce_pages.
Test Plan:
Without this patch applied, booting fails as follows (pseries guest on
Linux/ppc64le KVM host):
vtblk0: <VirtIO Block Adapter> numa-domain 0 on virtio_pci1
panic: Empty stailq 0x8ed4480->stqh_last is 0, not head's first field
address
cpuid = 0
time = 1
KDB: stack backtrace:
0xc00800000000bcc0: at kdb_backtrace+0x60
0xc00800000000bdd0: at vpanic+0x1d4
0xc00800000000be80: at panic+0x44
0xc00800000000beb0: at bus_dmamap_unload+0x394
0xc00800000000bf60: at vtblk_poll_request+0x16c
0xc00800000000bff0: at vtblk_attach_completed+0x208
0xc00800000000c220: at vtpci_legacy_probe_and_attach_child+0x224
0xc00800000000c270: at vtpci_legacy_attach+0x2c0
0xc00800000000c320: at device_attach+0x568
0xc00800000000c400: at bus_attach_children+0x8c
0xc00800000000c440: at ofw_pcibus_attach+0x398
0xc00800000000c550: at device_attach+0x568
0xc00800000000c630: at bus_attach_children+0x8c
0xc00800000000c670: at ofw_pcib_attach+0x68
0xc00800000000c6a0: at rtaspci_attach+0x18c
0xc00800000000c6f0: at device_attach+0x568
0xc00800000000c7d0: at bus_generic_new_pass+0x198
0xc00800000000c820: at bus_generic_new_pass+0x10c
0xc00800000000c870: at bus_generic_new_pass+0x10c
0xc00800000000c8c0: at root_bus_configure+0x6c
0xc00800000000c910: at configure+0x1c
0xc00800000000c940: at mi_startup+0x298
0xc00800000000ca50: at __start+0xfc
KDB: enter: panic
[ thread pid 0 tid 100000 ]
Stopped at kdb_enter+0x70: ori r0, r0, 0x0
With the patch applied to properly initialize the STAILQ unconditionally,
the assertion is no longer hit and the system boots as expected.
Reviewers: jhibbits, jhb, #powerpc, markj
Reviewed By: jhibbits, jhb, #powerpc, markj
Subscribers: imp, bdragon, luporl, alfredo, #powerpc
Tags: #powerpc
Differential Revision: https://reviews.freebsd.org/D48600
---
sys/powerpc/powerpc/busdma_machdep.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/sys/powerpc/powerpc/busdma_machdep.c
b/sys/powerpc/powerpc/busdma_machdep.c
index 34dcea8de9ee..65f90aa4affa 100644
--- a/sys/powerpc/powerpc/busdma_machdep.c
+++ b/sys/powerpc/powerpc/busdma_machdep.c
@@ -303,6 +303,9 @@ bus_dmamap_create(bus_dma_tag_t dmat, int flags,
bus_dmamap_t *mapp)
return (ENOMEM);
}
+ /* Initialize the new map */
+ STAILQ_INIT(&((*mapp)->bpages));
+
/*
* Bouncing might be required if the driver asks for an active
* exclusion region, a data alignment that is stricter than 1, and/or
@@ -319,9 +322,6 @@ bus_dmamap_create(bus_dma_tag_t dmat, int flags,
bus_dmamap_t *mapp)
}
bz = dmat->bounce_zone;
- /* Initialize the new map */
- STAILQ_INIT(&((*mapp)->bpages));
-
/*
* Attempt to add pages to our pool on a per-instance
* basis up to a sane limit.
