Re: [PATCH 3/3] dmaengine: ioatdma: Fix kmemleak in ioat_pci_probe()

[Andy Shevchenko]

On Fri, May 24, 2024 at 1:24 PM Nikita Shubin via B4 Relay
<devnull+n.shubin.yadro.com@xxxxxxxxxx> wrote:
>
> From: Nikita Shubin <n.shubin@xxxxxxxxx>
>
> If probing fails we end up with leaking ioatdma_device and each
> allocated channel.
>
> Following kmemleak is easy to be reproduced by injecting error in

easy to reproduce

an error

> ioat_alloc_chan_resources() when doing ioat_dma_self_test().
>
> unreferenced object 0xffff888014ad5800 (size 1024):
>   comm "modprobe", pid 73, jiffies 4294681749
>   hex dump (first 32 bytes):
>     00 10 00 13 80 88 ff ff 00 c0 3f 00 00 c9 ff ff  ..........?.....
>     00 ce 76 13 80 88 ff ff 00 00 00 00 00 00 00 00  ..v.............
>   backtrace (crc 1f353f55):
>     [<ffffffff827692ca>] kmemleak_alloc+0x4a/0x80
>     [<ffffffff81430600>] kmalloc_trace+0x270/0x2f0
>     [<ffffffffa000b7d1>] ioat_pci_probe+0xc1/0x1c0 [ioatdma]
>     [<ffffffff8199376a>] local_pci_probe+0x7a/0xe0
>     [<ffffffff81995189>] pci_call_probe+0xd9/0x2c0
>     [<ffffffff81995975>] pci_device_probe+0xa5/0x170
>     [<ffffffff81f5f89b>] really_probe+0x14b/0x510
>     [<ffffffff81f5fd4a>] __driver_probe_device+0xda/0x1f0
>     [<ffffffff81f5febf>] driver_probe_device+0x4f/0x120
>     [<ffffffff81f6028a>] __driver_attach+0x14a/0x2b0
>     [<ffffffff81f5c56c>] bus_for_each_dev+0xec/0x160
>     [<ffffffff81f5ee1b>] driver_attach+0x2b/0x40
>     [<ffffffff81f5e0d3>] bus_add_driver+0x1a3/0x300
>     [<ffffffff81f61db3>] driver_register+0xa3/0x1d0
>     [<ffffffff8199325b>] __pci_register_driver+0xeb/0x100
>     [<ffffffffa003009c>] 0xffffffffa003009c
>
> repeated for each ioatdma channel:
>
> unreferenced object 0xffff8880148e5c00 (size 512):
>   comm "modprobe", pid 73, jiffies 4294681751
>   hex dump (first 32 bytes):
>     40 58 ad 14 80 88 ff ff 00 00 00 00 00 00 00 00  @X..............
>     01 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace (crc fbc62789):
>     [<ffffffff827692ca>] kmemleak_alloc+0x4a/0x80
>     [<ffffffff81430600>] kmalloc_trace+0x270/0x2f0
>     [<ffffffffa0009641>] ioat_enumerate_channels+0x101/0x2d0 [ioatdma]
>     [<ffffffffa000b266>] ioat3_dma_probe+0x4d6/0x970 [ioatdma]
>     [<ffffffffa000b891>] ioat_pci_probe+0x181/0x1c0 [ioatdma]
>     [<ffffffff8199376a>] local_pci_probe+0x7a/0xe0
>     [<ffffffff81995189>] pci_call_probe+0xd9/0x2c0
>     [<ffffffff81995975>] pci_device_probe+0xa5/0x170
>     [<ffffffff81f5f89b>] really_probe+0x14b/0x510
>     [<ffffffff81f5fd4a>] __driver_probe_device+0xda/0x1f0
>     [<ffffffff81f5febf>] driver_probe_device+0x4f/0x120
>     [<ffffffff81f6028a>] __driver_attach+0x14a/0x2b0
>     [<ffffffff81f5c56c>] bus_for_each_dev+0xec/0x160
>     [<ffffffff81f5ee1b>] driver_attach+0x2b/0x40
>     [<ffffffff81f5e0d3>] bus_add_driver+0x1a3/0x300
>     [<ffffffff81f61db3>] driver_register+0xa3/0x1d0

Please, read
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#backtraces-in-commit-messages
and follow the advice given there.

..

> +       int err, i;

Why signed?

-- 
With Best Regards,
Andy Shevchenko