2023-06-29 12:31:50

by GONG, Ruiqi

Subject: [PATCH] ipmi_si: fix a memleak in try_smi_init()

From: Yi Yang <[email protected]>

Kmemleak reported the following leak info in try_smi_init():

unreferenced object 0xffff00018ecf9400 (size 1024):
comm "modprobe", pid 2707763, jiffies 4300851415 (age 773.308s)
backtrace:
[<000000004ca5b312>] __kmalloc+0x4b8/0x7b0
[<00000000953b1072>] try_smi_init+0x148/0x5dc [ipmi_si]
[<000000006460d325>] 0xffff800081b10148
[<0000000039206ea5>] do_one_initcall+0x64/0x2a4
[<00000000601399ce>] do_init_module+0x50/0x300
[<000000003c12ba3c>] load_module+0x7a8/0x9e0
[<00000000c246fffe>] __se_sys_init_module+0x104/0x180
[<00000000eea99093>] __arm64_sys_init_module+0x24/0x30
[<0000000021b1ef87>] el0_svc_common.constprop.0+0x94/0x250
[<0000000070f4f8b7>] do_el0_svc+0x48/0xe0
[<000000005a05337f>] el0_svc+0x24/0x3c
[<000000005eb248d6>] el0_sync_handler+0x160/0x164
[<0000000030a59039>] el0_sync+0x160/0x180

The problem was that when an error occurred before handlers registration
and after allocating `new_smi->si_sm`, the variable wouldn't be freed in
the error handling afterwards since `shutdown_smi()` hadn't been
registered yet. Fix it by adding a `kfree()` in the error handling path
in `try_smi_init()`.

Cc: [email protected] # 4.19+
Fixes: 7960f18a5647 ("ipmi_si: Convert over to a shutdown handler")
Signed-off-by: Yi Yang <[email protected]>
Co-developed-by: GONG, Ruiqi <[email protected]>
Signed-off-by: GONG, Ruiqi <[email protected]>
---
drivers/char/ipmi/ipmi_si_intf.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index abddd7e43a9a..5cd031f3fc97 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -2082,6 +2082,11 @@ static int try_smi_init(struct smi_info *new_smi)
new_smi->io.io_cleanup = NULL;
}

+ if (rv && new_smi->si_sm) {
+ kfree(new_smi->si_sm);
+ new_smi->si_sm = NULL;
+ }
+
return rv;
}

--
2.25.1

2023-06-29 13:24:16

by Corey Minyard

Subject: Re: [PATCH] ipmi_si: fix a memleak in try_smi_init()

On Thu, Jun 29, 2023 at 08:33:28PM +0800, GONG, Ruiqi wrote:
> From: Yi Yang <[email protected]>
>
> Kmemleak reported the following leak info in try_smi_init():
>
> unreferenced object 0xffff00018ecf9400 (size 1024):
> comm "modprobe", pid 2707763, jiffies 4300851415 (age 773.308s)
> backtrace:
> [<000000004ca5b312>] __kmalloc+0x4b8/0x7b0
> [<00000000953b1072>] try_smi_init+0x148/0x5dc [ipmi_si]
> [<000000006460d325>] 0xffff800081b10148
> [<0000000039206ea5>] do_one_initcall+0x64/0x2a4
> [<00000000601399ce>] do_init_module+0x50/0x300
> [<000000003c12ba3c>] load_module+0x7a8/0x9e0
> [<00000000c246fffe>] __se_sys_init_module+0x104/0x180
> [<00000000eea99093>] __arm64_sys_init_module+0x24/0x30
> [<0000000021b1ef87>] el0_svc_common.constprop.0+0x94/0x250
> [<0000000070f4f8b7>] do_el0_svc+0x48/0xe0
> [<000000005a05337f>] el0_svc+0x24/0x3c
> [<000000005eb248d6>] el0_sync_handler+0x160/0x164
> [<0000000030a59039>] el0_sync+0x160/0x180
>
> The problem was that when an error occurred before handlers registration
> and after allocating `new_smi->si_sm`, the variable wouldn't be freed in
> the error handling afterwards since `shutdown_smi()` hadn't been
> registered yet. Fix it by adding a `kfree()` in the error handling path
> in `try_smi_init()`.

Thanks, I have included this. And thanks for handling the stable thing,
too.

-corey

>
> Cc: [email protected] # 4.19+
> Fixes: 7960f18a5647 ("ipmi_si: Convert over to a shutdown handler")
> Signed-off-by: Yi Yang <[email protected]>
> Co-developed-by: GONG, Ruiqi <[email protected]>
> Signed-off-by: GONG, Ruiqi <[email protected]>
> ---
> drivers/char/ipmi/ipmi_si_intf.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
> index abddd7e43a9a..5cd031f3fc97 100644
> --- a/drivers/char/ipmi/ipmi_si_intf.c
> +++ b/drivers/char/ipmi/ipmi_si_intf.c
> @@ -2082,6 +2082,11 @@ static int try_smi_init(struct smi_info *new_smi)
> new_smi->io.io_cleanup = NULL;
> }
>
> + if (rv && new_smi->si_sm) {
> + kfree(new_smi->si_sm);
> + new_smi->si_sm = NULL;
> + }
> +
> return rv;
> }
>
> --
> 2.25.1
>