| Message ID | 20240424033449.168398-2-xin.wang2@amd.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Remaining patches for dynamic node programming using overlay dtbo | expand |
On 24.04.2024 05:34, Henry Wang wrote: > --- a/xen/common/dt-overlay.c > +++ b/xen/common/dt-overlay.c > @@ -381,9 +381,14 @@ static int remove_node_resources(struct dt_device_node *device_node) > { > if ( dt_device_is_protected(device_node) ) > { > + write_lock(&dt_host_lock); > rc = iommu_remove_dt_device(device_node); Any particular reason you add two call sites to the unlock function, instead of putting it here? Jan > if ( rc < 0 ) > + { > + write_unlock(&dt_host_lock); > return rc; > + } > + write_unlock(&dt_host_lock); > } > } >
Hi Jan, On 4/24/2024 1:58 PM, Jan Beulich wrote: > On 24.04.2024 05:34, Henry Wang wrote: >> --- a/xen/common/dt-overlay.c >> +++ b/xen/common/dt-overlay.c >> @@ -381,9 +381,14 @@ static int remove_node_resources(struct dt_device_node *device_node) >> { >> if ( dt_device_is_protected(device_node) ) >> { >> + write_lock(&dt_host_lock); >> rc = iommu_remove_dt_device(device_node); > Any particular reason you add two call sites to the unlock function, > instead of putting it here? Oh...you are correct. It is indeed better to put the unlock here. If this is the only comment for this patch, can I respin this only patch as a v1.1 or would one of the committers be ok to fix on commit? Sorry for the trouble and thanks for the suggestion. Kind regards, Henry > Jan > >> if ( rc < 0 ) >> + { >> + write_unlock(&dt_host_lock); >> return rc; >> + } >> + write_unlock(&dt_host_lock); >> } >> } >>
diff --git a/xen/common/dt-overlay.c b/xen/common/dt-overlay.c index 1b197381f6..39e4ba59dd 100644 --- a/xen/common/dt-overlay.c +++ b/xen/common/dt-overlay.c @@ -381,9 +381,14 @@ static int remove_node_resources(struct dt_device_node *device_node) { if ( dt_device_is_protected(device_node) ) { + write_lock(&dt_host_lock); rc = iommu_remove_dt_device(device_node); if ( rc < 0 ) + { + write_unlock(&dt_host_lock); return rc; + } + write_unlock(&dt_host_lock); } }
If CONFIG_DEBUG=y, below assertion will be triggered: (XEN) Assertion 'rw_is_locked(&dt_host_lock)' failed at drivers/passthrough/device_tree.c:146 (XEN) ----[ Xen-4.19-unstable arm64 debug=y Not tainted ]---- (XEN) CPU: 0 (XEN) PC: 00000a0000257418 iommu_remove_dt_device+0x8c/0xd4 (XEN) LR: 00000a00002573a0 (XEN) SP: 00008000fff7fb30 (XEN) CPSR: 0000000000000249 MODE:64-bit EL2h (Hypervisor, handler) [...] (XEN) Xen call trace: (XEN) [<00000a0000257418>] iommu_remove_dt_device+0x8c/0xd4 (PC) (XEN) [<00000a00002573a0>] iommu_remove_dt_device+0x14/0xd4 (LR) (XEN) [<00000a000020797c>] dt-overlay.c#remove_node_resources+0x8c/0x90 (XEN) [<00000a0000207f14>] dt-overlay.c#remove_nodes+0x524/0x648 (XEN) [<00000a0000208460>] dt_overlay_sysctl+0x428/0xc68 (XEN) [<00000a00002707f8>] arch_do_sysctl+0x1c/0x2c (XEN) [<00000a0000230b40>] do_sysctl+0x96c/0x9ec (XEN) [<00000a0000271e08>] traps.c#do_trap_hypercall+0x1e8/0x288 (XEN) [<00000a0000273490>] do_trap_guest_sync+0x448/0x63c (XEN) [<00000a000025c480>] entry.o#guest_sync_slowpath+0xa8/0xd8 (XEN) (XEN) (XEN) **************************************** (XEN) Panic on CPU 0: (XEN) Assertion 'rw_is_locked(&dt_host_lock)' failed at drivers/passthrough/device_tree.c:146 (XEN) **************************************** This is because iommu_remove_dt_device() is called without taking the dt_host_lock. Fix the issue by taking and releasing the lock properly. Fixes: 7e5c4a8b86f1 ("xen/arm: Implement device tree node removal functionalities") Signed-off-by: Henry Wang <xin.wang2@amd.com> --- xen/common/dt-overlay.c | 5 +++++ 1 file changed, 5 insertions(+)