| Message ID | 20191022071153.21118-1-kishon@ti.com |
|---|---|
| State | Accepted |
| Commit | 8247470772beb38822f226c99a2ed8c195f6b438 |
| Headers | show |
| Series | clk: Fix memory leak in clk_unregister() | expand |
Quoting Kishon Vijay Abraham I (2019-10-22 00:11:53) > Memory allocated in alloc_clk() for 'struct clk' and > 'const char *con_id' while invoking clk_register() is never freed > in clk_unregister(), resulting in kmemleak showing the following > backtrace. > > backtrace: > [<00000000546f5dd0>] kmem_cache_alloc+0x18c/0x270 > [<0000000073a32862>] alloc_clk+0x30/0x70 > [<0000000082942480>] __clk_register+0xc8/0x760 > [<000000005c859fca>] devm_clk_register+0x54/0xb0 > [<00000000868834a8>] 0xffff800008c60950 > [<00000000d5a80534>] platform_drv_probe+0x50/0xa0 > [<000000001b3889fc>] really_probe+0x108/0x348 > [<00000000953fa60a>] driver_probe_device+0x58/0x100 > [<0000000008acc17c>] device_driver_attach+0x6c/0x90 > [<0000000022813df3>] __driver_attach+0x84/0xc8 > [<00000000448d5443>] bus_for_each_dev+0x74/0xc8 > [<00000000294aa93f>] driver_attach+0x20/0x28 > [<00000000e5e52626>] bus_add_driver+0x148/0x1f0 > [<000000001de21efc>] driver_register+0x60/0x110 > [<00000000af07c068>] __platform_driver_register+0x40/0x48 > [<0000000060fa80ee>] 0xffff800008c66020 > > Fix it here. Do you have some Fixes tag for this? Looks OK to me, but I wonder if we should also assign hw->clk to NULL after unregister frees it. There are probably other problems around unregistration and reference counting that we haven't found so far so I'm worried this doesn't solve all the problems by just freeing the clk pointer. For example, anything referencing the clk pointer freed here will now start trying to dereference freed memory. For most cases we've replaced struct clk with struct clk_core in the clk framework so I hope this pointer isn't used very much at all. A quick grep shows that it is returned from clk_get_parent() and __clk_lookup(). We really need to kill off __clk_lookup() and replace it with something else, and clk_get_parent() needs to generate a different clk and have callers call clk_put() on the returned pointer. Long story short I think this is OK!
Quoting Kishon Vijay Abraham I (2019-10-22 00:11:53) > Memory allocated in alloc_clk() for 'struct clk' and > 'const char *con_id' while invoking clk_register() is never freed > in clk_unregister(), resulting in kmemleak showing the following > backtrace. > > backtrace: > [<00000000546f5dd0>] kmem_cache_alloc+0x18c/0x270 > [<0000000073a32862>] alloc_clk+0x30/0x70 > [<0000000082942480>] __clk_register+0xc8/0x760 > [<000000005c859fca>] devm_clk_register+0x54/0xb0 > [<00000000868834a8>] 0xffff800008c60950 > [<00000000d5a80534>] platform_drv_probe+0x50/0xa0 > [<000000001b3889fc>] really_probe+0x108/0x348 > [<00000000953fa60a>] driver_probe_device+0x58/0x100 > [<0000000008acc17c>] device_driver_attach+0x6c/0x90 > [<0000000022813df3>] __driver_attach+0x84/0xc8 > [<00000000448d5443>] bus_for_each_dev+0x74/0xc8 > [<00000000294aa93f>] driver_attach+0x20/0x28 > [<00000000e5e52626>] bus_add_driver+0x148/0x1f0 > [<000000001de21efc>] driver_register+0x60/0x110 > [<00000000af07c068>] __platform_driver_register+0x40/0x48 > [<0000000060fa80ee>] 0xffff800008c66020 > > Fix it here. > > Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> > Cc: Tero Kristo <t-kristo@ti.com> > Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com> > --- Applied to clk-next I also added a fixes tag for the best I could guess.
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 1c677d7f7f53..2f2eea26c375 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -3879,6 +3879,7 @@ void clk_unregister(struct clk *clk) __func__, clk->core->name); kref_put(&clk->core->ref, __clk_release); + free_clk(clk); unlock: clk_prepare_unlock(); }
Memory allocated in alloc_clk() for 'struct clk' and 'const char *con_id' while invoking clk_register() is never freed in clk_unregister(), resulting in kmemleak showing the following backtrace. backtrace: [<00000000546f5dd0>] kmem_cache_alloc+0x18c/0x270 [<0000000073a32862>] alloc_clk+0x30/0x70 [<0000000082942480>] __clk_register+0xc8/0x760 [<000000005c859fca>] devm_clk_register+0x54/0xb0 [<00000000868834a8>] 0xffff800008c60950 [<00000000d5a80534>] platform_drv_probe+0x50/0xa0 [<000000001b3889fc>] really_probe+0x108/0x348 [<00000000953fa60a>] driver_probe_device+0x58/0x100 [<0000000008acc17c>] device_driver_attach+0x6c/0x90 [<0000000022813df3>] __driver_attach+0x84/0xc8 [<00000000448d5443>] bus_for_each_dev+0x74/0xc8 [<00000000294aa93f>] driver_attach+0x20/0x28 [<00000000e5e52626>] bus_add_driver+0x148/0x1f0 [<000000001de21efc>] driver_register+0x60/0x110 [<00000000af07c068>] __platform_driver_register+0x40/0x48 [<0000000060fa80ee>] 0xffff800008c66020 Fix it here. Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: Tero Kristo <t-kristo@ti.com> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com> --- drivers/clk/clk.c | 1 + 1 file changed, 1 insertion(+) -- 2.17.1