Re: [PATCH] ARM: 9192/1: amba: fix memory leak in amba_device_try_add()
From: Kefeng Wang
Date: Mon May 23 2022 - 22:43:25 EST
On 2022/5/24 10:33, Guenter Roeck wrote:
On 5/23/22 18:57, Kefeng Wang wrote:
On 2022/5/24 5:17, Guenter Roeck wrote:
On Mon, Apr 18, 2022 at 07:07:14AM +0100, Wang Kefeng wrote:
If amba_device_try_add() return error code (not EPROBE_DEFER),
memory leak occurred when amba device fails to read periphid.
This patch results in a refcount underflow.
NET: Registered PF_NETLINK/PF_ROUTE protocol family
DMA: preallocated 256 KiB pool for atomic coherent allocations
platform vga: Fixing up cyclic dependency with bridge
OF: amba_device_add() failed (-19) for /amba/smc@10100000
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at lib/refcount.c:28
of_platform_bus_create+0x33c/0x3dc
refcount_t: underflow; use-after-free.
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 5.18.0-next-20220523 #1
Hardware name: ARM-Versatile (Device Tree Support)
unwind_backtrace from show_stack+0x10/0x14
show_stack from dump_stack_lvl+0x38/0x5c
dump_stack_lvl from __warn+0xc8/0x1d4
__warn from warn_slowpath_fmt+0x90/0xc8
warn_slowpath_fmt from of_platform_bus_create+0x33c/0x3dc
of_platform_bus_create from of_platform_bus_create+0x1ec/0x3dc
of_platform_bus_create from of_platform_populate+0x68/0xd8
of_platform_populate from customize_machine+0x1c/0x30
customize_machine from do_one_initcall+0x8c/0x2fc
do_one_initcall from kernel_init_freeable+0x190/0x220
kernel_init_freeable from kernel_init+0x10/0x108
kernel_init from ret_from_fork+0x14/0x3c
Thank, I use vexpress-v2p-ca15-tc1 and can't reproduce , but after
check the code,
amba_device_try_add() is called amba_deferred_retry() and
amba_device_add(),
1) for amba_device_add(), called by of_amba_device_create() and
amba_handler_attach(),
which has called amba_device_put() to release resource when meet
error, my
patch leads to the above issue.
2) for amba_deferred_retry(), it only releases the struct
deferred_device, but forget
to call amba_device_put() to release amba device and device name
so we only need to call amba_device_put() in amba_deferred_retry(),
could you
help me to try the following patch, thanks.
It doesn't apply; it looks like you used cut-and-paste, which replaced
tabs with spaces. I tried to fix it up, but it didn't work.
Please send a clean patch.
Please use this one,
https://lore.kernel.org/all/20220524025139.40212-1-wangkefeng.wang@xxxxxxxxxx/T/#u
Thanks,
Guenter
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index 0e3ed5eb367b..0cb20324da16 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -493,13 +493,8 @@ static int amba_device_try_add(struct
amba_device *dev, struct resource *parent)
goto skip_probe;
ret = amba_read_periphid(dev);
- if (ret) {
- if (ret != -EPROBE_DEFER) {
- amba_device_put(dev);
- goto err_out;
- }
+ if (ret)
goto err_release;
- }
skip_probe:
ret = device_add(&dev->dev);
@@ -546,6 +541,7 @@ static int amba_deferred_retry(void)
continue;
list_del_init(&ddev->node);
+ amba_device_put(ddev->dev);
kfree(ddev);
}
Guenter
---
# bad: [cc63e8e92cb872081f249ea16e6c460642f3e4fb] Add linux-next
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git bisect start 'HEAD' 'v5.18'
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# bad: [b6f21d14f1ac1261579b691673a0c823275cbaf8] ARM: 9204/2:
module: Add all unwind tables when load module
git bisect bad b6f21d14f1ac1261579b691673a0c823275cbaf8
# bad: [c4f486f1e7b34b27ec578494a236061b337d50ae] ARM: 9198/1:
spectre-bhb: simplify BPIALL vector macro
git bisect bad c4f486f1e7b34b27ec578494a236061b337d50ae
# bad: [7719a68b2fa404fa8af6b0b7119a38c406c74858] ARM: 9192/1: amba:
fix memory leak in amba_device_try_add()
git bisect bad 7719a68b2fa404fa8af6b0b7119a38c406c74858
# good: [1f44de0f5e309e8699b569b49a8e89ef4e7527c7] ARM: 9193/1:
amba: Add amba_read_periphid() helper
git bisect good 1f44de0f5e309e8699b569b49a8e89ef4e7527c7
# first bad commit: [7719a68b2fa404fa8af6b0b7119a38c406c74858] ARM:
9192/1: amba: fix memory leak in amba_device_try_add()
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