lkml.org 
[lkml]   [2022]   [Jun]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.17 507/772] drivers/base/memory: fix an unlikely reference counting issue in __add_memory_block()
    Date
    From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

    [ Upstream commit f47f758cff59c68015d6b9b9c077110df7c2c828 ]

    __add_memory_block() calls both put_device() and device_unregister() when
    storing the memory block into the xarray. This is incorrect because
    xarray doesn't take an additional reference and device_unregister()
    already calls put_device().

    Triggering the issue looks really unlikely and its only effect should be
    to log a spurious warning about a ref counted issue.

    Link: https://lkml.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@wanadoo.fr
    Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup")
    Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
    Acked-by: Michal Hocko <mhocko@suse.com>
    Reviewed-by: David Hildenbrand <david@redhat.com>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: "Rafael J. Wysocki" <rafael@kernel.org>
    Cc: Scott Cheloha <cheloha@linux.vnet.ibm.com>
    Cc: Nathan Lynch <nathanl@linux.ibm.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/base/memory.c | 5 ++---
    1 file changed, 2 insertions(+), 3 deletions(-)

    diff --git a/drivers/base/memory.c b/drivers/base/memory.c
    index 60c38f9cf1a7..c0d501a3a714 100644
    --- a/drivers/base/memory.c
    +++ b/drivers/base/memory.c
    @@ -634,10 +634,9 @@ int register_memory(struct memory_block *memory)
    }
    ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
    GFP_KERNEL));
    - if (ret) {
    - put_device(&memory->dev);
    + if (ret)
    device_unregister(&memory->dev);
    - }
    +
    return ret;
    }

    --
    2.35.1


    \
     
     \ /
      Last update: 2022-06-07 23:24    [W:4.066 / U:0.220 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site