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[PATCH V2] xen: Drop out of coroutine context xen_invalidate_map_cache_entry

Peng Fan (OSS) posted 1 patch 10 months, 1 week ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20240124021450.21656-1-peng.fan@oss.nxp.com
Maintainers: Stefano Stabellini <sstabellini@kernel.org>, Anthony Perard <anthony.perard@citrix.com>, Paul Durrant <paul@xen.org>
hw/xen/xen-mapcache.c | 30 ++++++++++++++++++++++++++++--
1 file changed, 28 insertions(+), 2 deletions(-)
[PATCH V2] xen: Drop out of coroutine context xen_invalidate_map_cache_entry
Posted by Peng Fan (OSS) 10 months, 1 week ago 
From: Peng Fan <peng.fan@nxp.com>

xen_invalidate_map_cache_entry is not expected to run in a
coroutine. Without this, there is crash:

    signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
    threadid=<optimized out>) at pthread_kill.c:78
    at /usr/src/debug/glibc/2.38+git-r0/sysdeps/posix/raise.c:26
    fmt=0xffff9e1ca8a8 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n",
    assertion=assertion@entry=0xaaaae0d25740 "!qemu_in_coroutine()",
    file=file@entry=0xaaaae0d301a8 "../qemu-xen-dir-remote/block/graph-lock.c", line=line@entry=260,
    function=function@entry=0xaaaae0e522c0 <__PRETTY_FUNCTION__.3> "bdrv_graph_rdlock_main_loop") at assert.c:92
    assertion=assertion@entry=0xaaaae0d25740 "!qemu_in_coroutine()",
    file=file@entry=0xaaaae0d301a8 "../qemu-xen-dir-remote/block/graph-lock.c", line=line@entry=260,
    function=function@entry=0xaaaae0e522c0 <__PRETTY_FUNCTION__.3> "bdrv_graph_rdlock_main_loop") at assert.c:101
    at ../qemu-xen-dir-remote/block/graph-lock.c:260
    at /home/Freenix/work/sw-stash/xen/upstream/tools/qemu-xen-dir-remote/include/block/graph-lock.h:259
    host=host@entry=0xffff742c8000, size=size@entry=2097152)
    at ../qemu-xen-dir-remote/block/io.c:3362
    host=0xffff742c8000, size=2097152)
    at ../qemu-xen-dir-remote/block/block-backend.c:2859
    host=<optimized out>, size=<optimized out>, max_size=<optimized out>)
    at ../qemu-xen-dir-remote/block/block-ram-registrar.c:33
    size=2097152, max_size=2097152)
    at ../qemu-xen-dir-remote/hw/core/numa.c:883
    buffer=buffer@entry=0xffff743c5000 "")
    at ../qemu-xen-dir-remote/hw/xen/xen-mapcache.c:475
    buffer=buffer@entry=0xffff743c5000 "")
    at ../qemu-xen-dir-remote/hw/xen/xen-mapcache.c:487
    as=as@entry=0xaaaae1ca3ae8 <address_space_memory>, buffer=0xffff743c5000,
    len=<optimized out>, is_write=is_write@entry=true,
    access_len=access_len@entry=32768)
    at ../qemu-xen-dir-remote/system/physmem.c:3199
    dir=DMA_DIRECTION_FROM_DEVICE, len=<optimized out>,
    buffer=<optimized out>, as=0xaaaae1ca3ae8 <address_space_memory>)
    at /home/Freenix/work/sw-stash/xen/upstream/tools/qemu-xen-dir-remote/include/sysemu/dma.h:236
    elem=elem@entry=0xaaaaf620aa30, len=len@entry=32769)
    at ../qemu-xen-dir-remote/hw/virtio/virtio.c:758
    elem=elem@entry=0xaaaaf620aa30, len=len@entry=32769, idx=idx@entry=0)
    at ../qemu-xen-dir-remote/hw/virtio/virtio.c:919
    elem=elem@entry=0xaaaaf620aa30, len=32769)
    at ../qemu-xen-dir-remote/hw/virtio/virtio.c:994
    req=req@entry=0xaaaaf620aa30, status=status@entry=0 '\000')
    at ../qemu-xen-dir-remote/hw/block/virtio-blk.c:67
    ret=0) at ../qemu-xen-dir-remote/hw/block/virtio-blk.c:136
    at ../qemu-xen-dir-remote/block/block-backend.c:1559
--Type <RET> for more, q to quit, c to continue without paging--
    at ../qemu-xen-dir-remote/block/block-backend.c:1614
    i1=<optimized out>) at ../qemu-xen-dir-remote/util/coroutine-ucontext.c:177
    at ../sysdeps/unix/sysv/linux/aarch64/setcontext.S:123

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---

V2:
 Drop unused ret in XenMapCacheData (thanks Stefano)

 hw/xen/xen-mapcache.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/hw/xen/xen-mapcache.c b/hw/xen/xen-mapcache.c
index f7d974677d..8d62b3d2ed 100644
--- a/hw/xen/xen-mapcache.c
+++ b/hw/xen/xen-mapcache.c
@@ -481,11 +481,37 @@ static void xen_invalidate_map_cache_entry_unlocked(uint8_t *buffer)
     g_free(entry);
 }
 
-void xen_invalidate_map_cache_entry(uint8_t *buffer)
+typedef struct XenMapCacheData {
+    Coroutine *co;
+    uint8_t *buffer;
+} XenMapCacheData;
+
+static void xen_invalidate_map_cache_entry_bh(void *opaque)
 {
+    XenMapCacheData *data = opaque;
+
     mapcache_lock();
-    xen_invalidate_map_cache_entry_unlocked(buffer);
+    xen_invalidate_map_cache_entry_unlocked(data->buffer);
     mapcache_unlock();
+
+    aio_co_wake(data->co);
+}
+
+void coroutine_mixed_fn xen_invalidate_map_cache_entry(uint8_t *buffer)
+{
+    if (qemu_in_coroutine()) {
+        XenMapCacheData data = {
+            .co = qemu_coroutine_self(),
+            .buffer = buffer,
+        };
+        aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
+                                xen_invalidate_map_cache_entry_bh, &data);
+        qemu_coroutine_yield();
+    } else {
+        mapcache_lock();
+        xen_invalidate_map_cache_entry_unlocked(buffer);
+        mapcache_unlock();
+    }
 }
 
 void xen_invalidate_map_cache(void)
-- 
2.35.3
Re: [PATCH V2] xen: Drop out of coroutine context xen_invalidate_map_cache_entry
Posted by Stefano Stabellini 10 months, 1 week ago 
On Wed, 24 Jan 2024, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> xen_invalidate_map_cache_entry is not expected to run in a
> coroutine. Without this, there is crash:
> 
>     signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
>     threadid=<optimized out>) at pthread_kill.c:78
>     at /usr/src/debug/glibc/2.38+git-r0/sysdeps/posix/raise.c:26
>     fmt=0xffff9e1ca8a8 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n",
>     assertion=assertion@entry=0xaaaae0d25740 "!qemu_in_coroutine()",
>     file=file@entry=0xaaaae0d301a8 "../qemu-xen-dir-remote/block/graph-lock.c", line=line@entry=260,
>     function=function@entry=0xaaaae0e522c0 <__PRETTY_FUNCTION__.3> "bdrv_graph_rdlock_main_loop") at assert.c:92
>     assertion=assertion@entry=0xaaaae0d25740 "!qemu_in_coroutine()",
>     file=file@entry=0xaaaae0d301a8 "../qemu-xen-dir-remote/block/graph-lock.c", line=line@entry=260,
>     function=function@entry=0xaaaae0e522c0 <__PRETTY_FUNCTION__.3> "bdrv_graph_rdlock_main_loop") at assert.c:101
>     at ../qemu-xen-dir-remote/block/graph-lock.c:260
>     at /home/Freenix/work/sw-stash/xen/upstream/tools/qemu-xen-dir-remote/include/block/graph-lock.h:259
>     host=host@entry=0xffff742c8000, size=size@entry=2097152)
>     at ../qemu-xen-dir-remote/block/io.c:3362
>     host=0xffff742c8000, size=2097152)
>     at ../qemu-xen-dir-remote/block/block-backend.c:2859
>     host=<optimized out>, size=<optimized out>, max_size=<optimized out>)
>     at ../qemu-xen-dir-remote/block/block-ram-registrar.c:33
>     size=2097152, max_size=2097152)
>     at ../qemu-xen-dir-remote/hw/core/numa.c:883
>     buffer=buffer@entry=0xffff743c5000 "")
>     at ../qemu-xen-dir-remote/hw/xen/xen-mapcache.c:475
>     buffer=buffer@entry=0xffff743c5000 "")
>     at ../qemu-xen-dir-remote/hw/xen/xen-mapcache.c:487
>     as=as@entry=0xaaaae1ca3ae8 <address_space_memory>, buffer=0xffff743c5000,
>     len=<optimized out>, is_write=is_write@entry=true,
>     access_len=access_len@entry=32768)
>     at ../qemu-xen-dir-remote/system/physmem.c:3199
>     dir=DMA_DIRECTION_FROM_DEVICE, len=<optimized out>,
>     buffer=<optimized out>, as=0xaaaae1ca3ae8 <address_space_memory>)
>     at /home/Freenix/work/sw-stash/xen/upstream/tools/qemu-xen-dir-remote/include/sysemu/dma.h:236
>     elem=elem@entry=0xaaaaf620aa30, len=len@entry=32769)
>     at ../qemu-xen-dir-remote/hw/virtio/virtio.c:758
>     elem=elem@entry=0xaaaaf620aa30, len=len@entry=32769, idx=idx@entry=0)
>     at ../qemu-xen-dir-remote/hw/virtio/virtio.c:919
>     elem=elem@entry=0xaaaaf620aa30, len=32769)
>     at ../qemu-xen-dir-remote/hw/virtio/virtio.c:994
>     req=req@entry=0xaaaaf620aa30, status=status@entry=0 '\000')
>     at ../qemu-xen-dir-remote/hw/block/virtio-blk.c:67
>     ret=0) at ../qemu-xen-dir-remote/hw/block/virtio-blk.c:136
>     at ../qemu-xen-dir-remote/block/block-backend.c:1559
> --Type <RET> for more, q to quit, c to continue without paging--
>     at ../qemu-xen-dir-remote/block/block-backend.c:1614
>     i1=<optimized out>) at ../qemu-xen-dir-remote/util/coroutine-ucontext.c:177
>     at ../sysdeps/unix/sysv/linux/aarch64/setcontext.S:123
> 
> Signed-off-by: Peng Fan <peng.fan@nxp.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> 
> V2:
>  Drop unused ret in XenMapCacheData (thanks Stefano)
> 
>  hw/xen/xen-mapcache.c | 30 ++++++++++++++++++++++++++++--
>  1 file changed, 28 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/xen/xen-mapcache.c b/hw/xen/xen-mapcache.c
> index f7d974677d..8d62b3d2ed 100644
> --- a/hw/xen/xen-mapcache.c
> +++ b/hw/xen/xen-mapcache.c
> @@ -481,11 +481,37 @@ static void xen_invalidate_map_cache_entry_unlocked(uint8_t *buffer)
>      g_free(entry);
>  }
>  
> -void xen_invalidate_map_cache_entry(uint8_t *buffer)
> +typedef struct XenMapCacheData {
> +    Coroutine *co;
> +    uint8_t *buffer;
> +} XenMapCacheData;
> +
> +static void xen_invalidate_map_cache_entry_bh(void *opaque)
>  {
> +    XenMapCacheData *data = opaque;
> +
>      mapcache_lock();
> -    xen_invalidate_map_cache_entry_unlocked(buffer);
> +    xen_invalidate_map_cache_entry_unlocked(data->buffer);
>      mapcache_unlock();
> +
> +    aio_co_wake(data->co);
> +}
> +
> +void coroutine_mixed_fn xen_invalidate_map_cache_entry(uint8_t *buffer)
> +{
> +    if (qemu_in_coroutine()) {
> +        XenMapCacheData data = {
> +            .co = qemu_coroutine_self(),
> +            .buffer = buffer,
> +        };
> +        aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
> +                                xen_invalidate_map_cache_entry_bh, &data);
> +        qemu_coroutine_yield();
> +    } else {
> +        mapcache_lock();
> +        xen_invalidate_map_cache_entry_unlocked(buffer);
> +        mapcache_unlock();
> +    }
>  }
>  
>  void xen_invalidate_map_cache(void)
> -- 
> 2.35.3
>

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