[PATCH] nvme-multipath: Fix memory leak with ana_log_buf

[PATCH] nvme-multipath: Fix memory leak with ana_log_buf

[Logan Gunthorpe]

kmemleak reports a memory leak with the ana_log_buf allocated by
nvme_mpath_init():

unreferenced object 0xffff888120e94000 (size 8208):
  comm "nvme", pid 6884, jiffies 4295020435 (age 78786.312s)
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
      01 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<00000000e2360188>] kmalloc_order+0x97/0xc0
      [<0000000079b18dd4>] kmalloc_order_trace+0x24/0x100
      [<00000000f50c0406>] __kmalloc+0x24c/0x2d0
      [<00000000f31a10b9>] nvme_mpath_init+0x23c/0x2b0
      [<000000005802589e>] nvme_init_identify+0x75f/0x1600
      [<0000000058ef911b>] nvme_loop_configure_admin_queue+0x26d/0x280
      [<00000000673774b9>] nvme_loop_create_ctrl+0x2a7/0x710
      [<00000000f1c7a233>] nvmf_dev_write+0xc66/0x10b9
      [<000000004199f8d0>] __vfs_write+0x50/0xa0
      [<0000000065466fef>] vfs_write+0xf3/0x280
      [<00000000b0db9a8b>] ksys_write+0xc6/0x160
      [<0000000082156b91>] __x64_sys_write+0x43/0x50
      [<00000000c34fbb6d>] do_syscall_64+0x77/0x2f0
      [<00000000bbc574c9>] entry_SYSCALL_64_after_hwframe+0x49/0xbe

nvme_mpath_init() is called by nvme_init_identify() which is called in
multiple places (nvme_reset_work(), nvme_passthru_end(), etc). This
means nvme_mpath_init() may be called multiple times before
nvme_mpath_uninit() (which is only called on nvme_free_ctrl()).

When nvme_mpath_init() is called multiple times, it overwrites the
ana_log_buf pointer with a new allocation, thus leaking the previous
allocation.

To fix this, free ana_log_buf before allocating a new one.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
 drivers/nvme/host/multipath.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 797c18337d96..a11900cf3a36 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -715,6 +715,7 @@ int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 	}
 
 	INIT_WORK(&ctrl->ana_work, nvme_ana_work);
+	kfree(ctrl->ana_log_buf);
 	ctrl->ana_log_buf = kmalloc(ctrl->ana_log_size, GFP_KERNEL);
 	if (!ctrl->ana_log_buf) {
 		error = -ENOMEM;

base-commit: 11a48a5a18c63fd7621bb050228cebf13566e4d8
-- 
2.20.1


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Re: [PATCH] nvme-multipath: Fix memory leak with ana_log_buf

[Sagi Grimberg]

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

Keith, can you CC stable when applying?

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Re: [PATCH] nvme-multipath: Fix memory leak with ana_log_buf

[Logan Gunthorpe]

On 2020-02-20 2:12 p.m., Sagi Grimberg wrote:
> Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
> 
> Keith, can you CC stable when applying?

Oh, yeah, I should have added the tag:

Fixes: 0d0b660f214d ("nvme: add ANA support")

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Re: [PATCH] nvme-multipath: Fix memory leak with ana_log_buf

[Christoph Hellwig]

On Thu, Feb 20, 2020 at 01:29:53PM -0700, Logan Gunthorpe wrote:
> kmemleak reports a memory leak with the ana_log_buf allocated by
> nvme_mpath_init():

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

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Re: [PATCH] nvme-multipath: Fix memory leak with ana_log_buf

[Keith Busch]

On Thu, Feb 20, 2020 at 01:29:53PM -0700, Logan Gunthorpe wrote:
> kmemleak reports a memory leak with the ana_log_buf allocated by
> nvme_mpath_init():
> 
> unreferenced object 0xffff888120e94000 (size 8208):
>   comm "nvme", pid 6884, jiffies 4295020435 (age 78786.312s)
>     hex dump (first 32 bytes):
>       00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
>       01 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00  ................
>     backtrace:
>       [<00000000e2360188>] kmalloc_order+0x97/0xc0
>       [<0000000079b18dd4>] kmalloc_order_trace+0x24/0x100
>       [<00000000f50c0406>] __kmalloc+0x24c/0x2d0
>       [<00000000f31a10b9>] nvme_mpath_init+0x23c/0x2b0
>       [<000000005802589e>] nvme_init_identify+0x75f/0x1600
>       [<0000000058ef911b>] nvme_loop_configure_admin_queue+0x26d/0x280
>       [<00000000673774b9>] nvme_loop_create_ctrl+0x2a7/0x710
>       [<00000000f1c7a233>] nvmf_dev_write+0xc66/0x10b9
>       [<000000004199f8d0>] __vfs_write+0x50/0xa0
>       [<0000000065466fef>] vfs_write+0xf3/0x280
>       [<00000000b0db9a8b>] ksys_write+0xc6/0x160
>       [<0000000082156b91>] __x64_sys_write+0x43/0x50
>       [<00000000c34fbb6d>] do_syscall_64+0x77/0x2f0
>       [<00000000bbc574c9>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
> 
> nvme_mpath_init() is called by nvme_init_identify() which is called in
> multiple places (nvme_reset_work(), nvme_passthru_end(), etc). This
> means nvme_mpath_init() may be called multiple times before
> nvme_mpath_uninit() (which is only called on nvme_free_ctrl()).
> 
> When nvme_mpath_init() is called multiple times, it overwrites the
> ana_log_buf pointer with a new allocation, thus leaking the previous
> allocation.
> 
> To fix this, free ana_log_buf before allocating a new one.
> 
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>

Thanks, applied to 5.6-rc3 with the reviews and the fixes tag.

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