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author | Herve Codina <herve.codina@bootlin.com> | 2023-11-14 18:26:55 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-01-01 15:42:46 +0300 |
commit | 50ae1c470491481328363639c227020691469f29 (patch) | |
tree | 1dc2140d99e2cb0717de90bd6abc86fbd6b65c87 /drivers/watchdog/dw_wdt.c | |
parent | 9a6ed4ea985ac4b7a566faddeb16271b8ea54d36 (diff) | |
download | linux-50ae1c470491481328363639c227020691469f29.tar.xz |
lib/vsprintf: Fix %pfwf when current node refcount == 0
commit 5c47251e8c4903111608ddcba2a77c0c425c247c upstream.
A refcount issue can appeared in __fwnode_link_del() due to the
pr_debug() call:
WARNING: CPU: 0 PID: 901 at lib/refcount.c:25 refcount_warn_saturate+0xe5/0x110
Call Trace:
<TASK>
...
of_node_get+0x1e/0x30
of_fwnode_get+0x28/0x40
fwnode_full_name_string+0x34/0x90
fwnode_string+0xdb/0x140
...
vsnprintf+0x17b/0x630
...
__fwnode_link_del+0x25/0xa0
fwnode_links_purge+0x39/0xb0
of_node_release+0xd9/0x180
...
Indeed, an fwnode (of_node) is being destroyed and so, of_node_release()
is called because the of_node refcount reached 0.
From of_node_release() several function calls are done and lead to
a pr_debug() calls with %pfwf to print the fwnode full name.
The issue is not present if we change %pfwf to %pfwP.
To print the full name, %pfwf iterates over the current node and its
parents and obtain/drop a reference to all nodes involved.
In order to allow to print the full name (%pfwf) of a node while it is
being destroyed, do not obtain/drop a reference to this current node.
Fixes: a92eb7621b9f ("lib/vsprintf: Make use of fwnode API to obtain node names and separators")
Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20231114152655.409331-1-herve.codina@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/watchdog/dw_wdt.c')
0 files changed, 0 insertions, 0 deletions