[Xen-devel] [PATCH] libxl: fix issues in 38cd0664

[Wei Liu <wei.liu2@xxxxxxxxxx>]

A few issues were introduced in 38cd0664 ("libxl/arm: Add the size of
ACPI tables to maxmem"):

1. d_config was not properly initialised and disposed of.
2. using libxl_retrieve_domain_configuration caused thread to
   deadlock itself.

Fix those issues by:

1. properly initialise and dispose of d_config.
2. switch to use libxl__get_domain_configuration.

Note that in theory we can refactor libxl_retrieve_domain_configuration
a bit to get a function without locking, but up until the calculation of
extra memory only relies on static configuration, hence we use the
stored configuration only.

Reported-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Tested-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
CC: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Cc: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 tools/libxl/libxl.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 432e5d9..33c5e4c 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -4029,6 +4029,8 @@ int libxl_domain_setmaxmem(libxl_ctx *ctx, uint32_t 
domid, uint64_t max_memkb)
     libxl__domain_userdata_lock *lock = NULL;
     libxl_domain_config d_config;
 
+    libxl_domain_config_init(&d_config);
+
     CTX_LOCK;
 
     lock = libxl__lock_domain_userdata(gc, domid);
@@ -4054,7 +4056,7 @@ int libxl_domain_setmaxmem(libxl_ctx *ctx, uint32_t 
domid, uint64_t max_memkb)
         goto out;
     }
 
-    rc = libxl_retrieve_domain_configuration(ctx, domid, &d_config);
+    rc = libxl__get_domain_configuration(gc, domid, &d_config);
     if (rc < 0) {
         LOGE(ERROR, "unable to retrieve domain configuration");
         goto out;
@@ -4076,6 +4078,7 @@ int libxl_domain_setmaxmem(libxl_ctx *ctx, uint32_t 
domid, uint64_t max_memkb)
 
     rc = 0;
 out:
+    libxl_domain_config_dispose(&d_config);
     if (lock) libxl__unlock_domain_userdata(lock);
     CTX_UNLOCK;
     GC_FREE;
@@ -4177,6 +4180,8 @@ int libxl_set_memory_target(libxl_ctx *ctx, uint32_t 
domid,
     libxl__domain_userdata_lock *lock;
     libxl_domain_config d_config;
 
+    libxl_domain_config_init(&d_config);
+
     CTX_LOCK;
 
     lock = libxl__lock_domain_userdata(gc, domid);
@@ -4185,7 +4190,7 @@ int libxl_set_memory_target(libxl_ctx *ctx, uint32_t 
domid,
         goto out_no_transaction;
     }
 
-    rc = libxl_retrieve_domain_configuration(ctx, domid, &d_config);
+    rc = libxl__get_domain_configuration(gc, domid, &d_config);
     if (rc < 0) {
         LOGE(ERROR, "unable to retrieve domain configuration");
         goto out_no_transaction;
@@ -4318,6 +4323,7 @@ out:
             goto retry_transaction;
 
 out_no_transaction:
+    libxl_domain_config_dispose(&d_config);
     if (lock) libxl__unlock_domain_userdata(lock);
     CTX_UNLOCK;
     GC_FREE;
-- 
2.1.4


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