Re: [PATCH] bluez5: add patch to fix 8.56 gatt cache issue

Re: [PATCH] bluez5: add patch to fix 8.56 gatt cache issue

[Mengshi Wu]

Dear maintainers,

Please help review this patch. Sorry for bothering. Thanks

On 5/21/2026 2:22 PM, Mengshi Wu wrote:
> There is a timing issue to update DB Hash value.
> 
> The gatt_client_service_changed() callback in src/device.c is called
> from service_changed_complete() in gatt-client.c, which is invoked
> after db_hash_read_cb() has already updated the hash. Adding
> store_gatt_db(device) here guarantees the db is persisted with the
> correct, up-to-date hash for both the addition and removal cases.
> 
> Upstream-Status: Backport [https://github.com/bluez/bluez/commit/0fd01e98cf94616a5c1c39749314cdd4a1654687]
> Signed-off-by: Mengshi Wu <mengshi.wu@oss.qualcomm.com>
> ---
>  meta/recipes-connectivity/bluez5/bluez5.inc   |  1 +
>  ...x-stored-gatt-cache-DB-Hash-value-no.patch | 84 +++++++++++++++++++
>  2 files changed, 85 insertions(+)
>  create mode 100644 meta/recipes-connectivity/bluez5/bluez5/0001-src-device-Fix-stored-gatt-cache-DB-Hash-value-no.patch
> 
> diff --git a/meta/recipes-connectivity/bluez5/bluez5.inc b/meta/recipes-connectivity/bluez5/bluez5.inc
> index 87252b9..0ca793a 100644
> --- a/meta/recipes-connectivity/bluez5/bluez5.inc
> +++ b/meta/recipes-connectivity/bluez5/bluez5.inc
> @@ -71,6 +71,7 @@ SRC_URI = "${KERNELORG_MIRROR}/linux/bluetooth/bluez-${PV}.tar.xz \
>             file://0001-Revert-shared-shell-Don-t-init-input-for-non-interac.patch \
>             file://0001-tools-Work-around-broken-stdin-handling-in-home-made.patch \
>             file://0001-gatt-client-Fix-use-after-free-caused-by-reentrant-c.patch \
> +           file://0001-src-device-Fix-stored-gatt-cache-DB-Hash-value-no.patch    \
>             "
>  S = "${UNPACKDIR}/bluez-${PV}"
>  
> diff --git a/meta/recipes-connectivity/bluez5/bluez5/0001-src-device-Fix-stored-gatt-cache-DB-Hash-value-no.patch b/meta/recipes-connectivity/bluez5/bluez5/0001-src-device-Fix-stored-gatt-cache-DB-Hash-value-no.patch
> new file mode 100644
> index 0000000..dda9ec2
> --- /dev/null
> +++ b/meta/recipes-connectivity/bluez5/bluez5/0001-src-device-Fix-stored-gatt-cache-DB-Hash-value-no.patch
> @@ -0,0 +1,84 @@
> +From 9ec8cad56e47c0555a056e928e6568d543b3ae0c Mon Sep 17 00:00:00 2001
> +From: Mengshi Wu <mengshi.wu@oss.qualcomm.com>
> +Date: Wed, 1 Apr 2026 19:30:04 +0800
> +Subject: [PATCH v1] src/device: Fix stored gatt cache DB Hash value not update
> +MIME-Version: 1.0
> +Content-Type: text/plain; charset=UTF-8
> +Content-Transfer-Encoding: 8bit
> +
> +There is an asymmetry in behavior: when services are added during
> +the same connection (via Service Changed indication), the persistent
> +storage (disk) is not updated with the new DB hash, but when services
> +are removed, it is updated.
> +
> +During the same connection, We check DB hash value stored at
> +/var/lib/bluetooth/<adaptor addr>/cache/<remote addr>.
> +When established connection, the stored DB Hash value is A.Then we
> +add new services, the stored DB Hash value is still A which should
> +change to B. However, if we remove the existing services, the stored
> +DB Hash value changed to C.
> +
> +When performing addition, it goes like this:
> +
> +discover_primary_cb()
> +  └─> gatt_db_insert_service()      ← NEW service inserted into db
> +        └─> gatt_service_added()    ← callback fires immediately
> +              └─> store_gatt_db()   ← SAVED TO DISK (hash still OLD)
> +  ...
> +  └─> discovery_op_complete(success=true)
> +        └─> read_db_hash(op)             ← sends ATT Read By Type
> +              └─> [ATT response arrives]
> +                    └─> db_hash_read_cb()
> +                          ├─> gatt_db_attribute_write(op->hash, ...)
> +                          │     └─> hash UPDATED IN MEMORY
> +                          └─> discovery_op_complete(true, 0)
> +                                ├─> [no services to remove, no
> +                                │    store_gatt_db called]
> +                                └─> service_changed_complete()
> +
> +Whereas removal perform like this:
> +discovery_op_complete(success=true)  [1st call]
> +  └─> read_db_hash(op)
> +      └─> op->hash is NULL → sends ATT request → early return
> +...
> +[ATT response arrives]
> +db_hash_read_cb()
> +  └─> gatt_db_attribute_write(op->hash, ) ← hash UPDATED IN MEMORY
> +  └─> discovery_op_complete(true, 0)          [2nd call]
> +      └─> read_db_hash(op)  → op->hash already set → returns false
> +      └─> gatt_db_remove_service()
> +          └─> gatt_service_removed()
> +              └─> store_gatt_db() ← SAVED TO DISK (hash is NEW)
> +
> +There is a timing issue to update DB Hash value.
> +
> +The gatt_client_service_changed() callback in src/device.c is called
> +from service_changed_complete() in gatt-client.c, which is invoked
> +after db_hash_read_cb() has already updated the hash. Adding
> +store_gatt_db(device) here guarantees the db is persisted with the
> +correct, up-to-date hash for both the addition and removal cases.
> +
> +Signed-off-by: Mengshi Wu <mengshi.wu@oss.qualcomm.com>
> +---
> + src/device.c | 4 ++++
> + 1 file changed, 4 insertions(+)
> +
> +diff --git a/src/device.c b/src/device.c
> +index 3ea683667..cfbde307b 100644
> +--- a/src/device.c
> ++++ b/src/device.c
> +@@ -6267,7 +6267,11 @@ static void gatt_client_service_changed(uint16_t start_handle,
> + 							uint16_t end_handle,
> + 							void *user_data)
> + {
> ++	struct btd_device *device = user_data;
> ++
> + 	DBG("start 0x%04x, end: 0x%04x", start_handle, end_handle);
> ++
> ++	store_gatt_db(device);
> + }
> + 
> + static void gatt_debug(const char *str, void *user_data)
> +-- 
> +2.34.1
> +

Re: [OE-core] [PATCH] bluez5: add patch to fix 8.56 gatt cache issue

[Mathieu Dubois-Briand]

On Fri May 29, 2026 at 6:06 AM CEST, Mengshi Wu via lists.openembedded.org wrote:
> Dear maintainers,
>
> Please help review this patch. Sorry for bothering. Thanks
>
> On 5/21/2026 2:22 PM, Mengshi Wu wrote:

Hi,

This mail is not in my inbox, and it looks like it never reached the
mailing-list:
https://lore.kernel.org/openembedded-core/?q=bluez5%3A+add+patch+to+fix+8.56+gatt+cache+issue

Can you try to send it again?

Thanks,
Mathieu

-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [OE-core] [PATCH] bluez5: add patch to fix 8.56 gatt cache issue

[Mengshi Wu]

Hi,

Thanks for kindly reminder. I have resent it.

Best regards,
Mengshi Wu

On 5/29/2026 3:01 PM, Mathieu Dubois-Briand wrote:
> On Fri May 29, 2026 at 6:06 AM CEST, Mengshi Wu via lists.openembedded.org wrote:
>> Dear maintainers,
>>
>> Please help review this patch. Sorry for bothering. Thanks
>>
>> On 5/21/2026 2:22 PM, Mengshi Wu wrote:
> 
> Hi,
> 
> This mail is not in my inbox, and it looks like it never reached the
> mailing-list:
> https://lore.kernel.org/openembedded-core/?q=bluez5%3A+add+patch+to+fix+8.56+gatt+cache+issue
> 
> Can you try to send it again?
> 
> Thanks,
> Mathieu
> 

Re: [OE-core] [PATCH] bluez5: add patch to fix 8.56 gatt cache issue

[Mengshi Wu]

Hi,

It seems that all the patches I sent are blocked by the upstream email server.

----- The following addresses had permanent fatal errors ----- <openembedded-core@lists.openembedded.org>
(reason: 500 This message has been flagged as spam.)

Best regards,
Mengshi Wu

On 5/29/2026 6:07 PM, Mengshi Wu wrote:
> Hi,
> 
> Thanks for kindly reminder. I have resent it.
> 
> Best regards,
> Mengshi Wu
> 
> On 5/29/2026 3:01 PM, Mathieu Dubois-Briand wrote:
>> On Fri May 29, 2026 at 6:06 AM CEST, Mengshi Wu via lists.openembedded.org wrote:
>>> Dear maintainers,
>>>
>>> Please help review this patch. Sorry for bothering. Thanks
>>>
>>> On 5/21/2026 2:22 PM, Mengshi Wu wrote:
>>
>> Hi,
>>
>> This mail is not in my inbox, and it looks like it never reached the
>> mailing-list:
>> https://lore.kernel.org/openembedded-core/?q=bluez5%3A+add+patch+to+fix+8.56+gatt+cache+issue
>>
>> Can you try to send it again?
>>
>> Thanks,
>> Mathieu
>>
> 

Re: [OE-core] [PATCH] bluez5: add patch to fix 8.56 gatt cache issue

[Mathieu Dubois-Briand]

On Fri May 29, 2026 at 2:34 PM CEST, Mengshi Wu wrote:
> Hi,
>
> It seems that all the patches I sent are blocked by the upstream email server.
>
> ----- The following addresses had permanent fatal errors ----- <openembedded-core@lists.openembedded.org>
> (reason: 500 This message has been flagged as spam.)
>
> Best regards,
> Mengshi Wu
>

You can send a mail to the helpdesk: helpdesk@yoctoproject.org. Michael
might be able to help you on this point.

Thanks,
Mathieu

-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [OE-core] [PATCH] bluez5: add patch to fix 8.56 gatt cache issue

[Mengshi Wu]

OK, Thanks!

On 5/29/2026 10:16 PM, Mathieu Dubois-Briand wrote:
> On Fri May 29, 2026 at 2:34 PM CEST, Mengshi Wu wrote:
>> Hi,
>>
>> It seems that all the patches I sent are blocked by the upstream email server.
>>
>> ----- The following addresses had permanent fatal errors ----- <openembedded-core@lists.openembedded.org>
>> (reason: 500 This message has been flagged as spam.)
>>
>> Best regards,
>> Mengshi Wu
>>
> 
> You can send a mail to the helpdesk: helpdesk@yoctoproject.org. Michael
> might be able to help you on this point.
> 
> Thanks,
> Mathieu
> 

Re: [OE-core] [PATCH] bluez5: add patch to fix 8.56 gatt cache issue

[Mathieu Dubois-Briand]

On Fri May 29, 2026 at 6:06 AM CEST, Mengshi Wu via lists.openembedded.org wrote:
>> --- /dev/null
>> +++ b/meta/recipes-connectivity/bluez5/bluez5/0001-src-device-Fix-stored-gatt-cache-DB-Hash-value-no.patch
>> @@ -0,0 +1,84 @@
...
>> +          └─> gatt_service_removed()
>> +              └─> store_gatt_db() ← SAVED TO DISK (hash is NEW)
>> +
>> +There is a timing issue to update DB Hash value.
>> +
>> +The gatt_client_service_changed() callback in src/device.c is called
>> +from service_changed_complete() in gatt-client.c, which is invoked
>> +after db_hash_read_cb() has already updated the hash. Adding
>> +store_gatt_db(device) here guarantees the db is persisted with the
>> +correct, up-to-date hash for both the addition and removal cases.
>> +
>> +Signed-off-by: Mengshi Wu <mengshi.wu@oss.qualcomm.com>
>> +---

I also note you are missing the Upstream-Status line in this patch.

Thanks,
Mathieu

-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com