[PATCH 4.14 179/190] drivers/macintosh: Fix memleak in windfarm_pm112 driver

Greg Kroah-Hartman
2020-06-19T14:52:55Z

From: Michael Ellerman <mpe@ellerman.id.au>

commit 93900337b9ac2f4eca427eff6d187be2dc3b5551 upstream.

create_cpu_loop() calls smu_sat_get_sdb_partition() which does
kmalloc() and returns the allocated buffer. In fact it's called twice,
and neither buffer is freed.

This results in a memory leak as reported by Erhard:
unreferenced object 0xc00000047081f840 (size 32):
comm "kwindfarm", pid 203, jiffies 4294880630 (age 5552.877s)
hex dump (first 32 bytes):
c8 06 02 7f ff 02 ff 01 fb bf 00 41 00 20 00 00 ...........A. ..
00 07 89 37 00 a0 00 00 00 00 00 00 00 00 00 00 ...7............
backtrace:
[<0000000083f0a65c>] .smu_sat_get_sdb_partition+0xc4/0x2d0 [windfarm_smu_sat]
[<000000003010fcb7>] .pm112_wf_notify+0x104c/0x13bc [windfarm_pm112]
[<00000000b958b2dd>] .notifier_call_chain+0xa8/0x180
[<0000000070490868>] .blocking_notifier_call_chain+0x64/0x90
[<00000000131d8149>] .wf_thread_func+0x114/0x1a0
[<000000000d54838d>] .kthread+0x13c/0x190
[<00000000669b72bc>] .ret_from_kernel_thread+0x58/0x64
unreferenced object 0xc0000004737089f0 (size 16):
comm "kwindfarm", pid 203, jiffies 4294880879 (age 5552.050s)
hex dump (first 16 bytes):
c4 04 01 7f 22 11 e0 e6 ff 55 7b 12 ec 11 00 00 ...."....U{.....
backtrace:
[<0000000083f0a65c>] .smu_sat_get_sdb_partition+0xc4/0x2d0 [windfarm_smu_sat]
[<00000000b94ef7e1>] .pm112_wf_notify+0x1294/0x13bc [windfarm_pm112]
[<00000000b958b2dd>] .notifier_call_chain+0xa8/0x180
[<0000000070490868>] .blocking_notifier_call_chain+0x64/0x90
[<00000000131d8149>] .wf_thread_func+0x114/0x1a0
[<000000000d54838d>] .kthread+0x13c/0x190
[<00000000669b72bc>] .ret_from_kernel_thread+0x58/0x64

Fix it by rearranging the logic so we deal with each buffer
separately, which then makes it easy to free the buffer once we're
done with it.

Fixes: ac171c46667c ("[PATCH] powerpc: Thermal control for dual core G5s")
Cc: stable@vger.kernel.org # v2.6.16+
Reported-by: Erhard F. <erhard_f@mailbox.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Erhard F. <erhard_f@mailbox.org>
Link: https://lore.kernel.org/r/20200423060038.3308530-1-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/macintosh/windfarm_pm112.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)

--- a/drivers/macintosh/windfarm_pm112.c
+++ b/drivers/macintosh/windfarm_pm112.c
@@ -133,14 +133,6 @@ static int create_cpu_loop(int cpu)
s32 tmax;
int fmin;

- /* Get PID params from the appropriate SAT */
- hdr = smu_sat_get_sdb_partition(chip, 0xC8 + core, NULL);
- if (hdr == NULL) {
- printk(KERN_WARNING"windfarm: can't get CPU PID fan config\n");
- return -EINVAL;
- }
- piddata = (struct smu_sdbp_cpupiddata *)&hdr[1];
-
/* Get FVT params to get Tmax; if not found, assume default */
hdr = smu_sat_get_sdb_partition(chip, 0xC4 + core, NULL);
if (hdr) {
@@ -153,6 +145,16 @@ static int create_cpu_loop(int cpu)
if (tmax < cpu_all_tmax)
cpu_all_tmax = tmax;

+ kfree(hdr);
+
+ /* Get PID params from the appropriate SAT */
+ hdr = smu_sat_get_sdb_partition(chip, 0xC8 + core, NULL);
+ if (hdr == NULL) {
+ printk(KERN_WARNING"windfarm: can't get CPU PID fan config\n");
+ return -EINVAL;
+ }
+ piddata = (struct smu_sdbp_cpupiddata *)&hdr[1];
+
/*
* Darwin has a minimum fan speed of 1000 rpm for the 4-way and
* 515 for the 2-way. That appears to be overkill, so for now,
@@ -175,6 +177,9 @@ static int create_cpu_loop(int cpu)
pid.min = fmin;

wf_cpu_pid_init(&cpu_pid[cpu], &pid);
+
+ kfree(hdr);
+
return 0;
}