Re: + mm-revert-mm-shmem-fix-data-race-in-shmem_getattr.patch added to mm-hotfixes-unstable branch

[Hugh Dickins <hughd@google.com>]

On Fri, 15 Nov 2024, Andrew Morton wrote:
> 
> The patch titled
>      Subject: mm: revert "mm: shmem: fix data-race in shmem_getattr()"
> has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
>      mm-revert-mm-shmem-fix-data-race-in-shmem_getattr.patch
> 
> This patch will shortly appear at
>      https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-revert-mm-shmem-fix-data-race-in-shmem_getattr.patch
> 
> This patch will later appear in the mm-hotfixes-unstable branch at
>     git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> 
> Before you just go and hit "reply", please:
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> 
> *** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
> 
> The -mm tree is included into linux-next via the mm-everything
> branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> and is updated there every 2-3 working days
> 
> ------------------------------------------------------
> From: Andrew Morton <akpm@linux-foundation.org>
> Subject: mm: revert "mm: shmem: fix data-race in shmem_getattr()"
> Date: Fri Nov 15 04:57:24 PM PST 2024
> 
> Revert d949d1d14fa2 ("mm: shmem: fix data-race in shmem_getattr()") as
> suggested by Chuck [1].  It is causing deadlocks when accessing tmpfs over
> NFS.
> 
> Link: https://lkml.kernel.org/r/ZzdxKF39VEmXSSyN@tissot.1015granger.net [1]
> Fixes: https://lkml.kernel.org/r/ZzdxKF39VEmXSSyN@tissot.1015granger.net
> Cc: Chuck Lever <chuck.lever@oracle.com>
> Cc: Hugh Dickins <hughd@google.com>

Acked-by: Hugh Dickins <hughd@google.com>

Thanks Andrew, I was just in the course of preparing the same
to rush to Linus: I'll leave that to you now.

> Cc: Jeongjun Park <aha310510@gmail.com>
> Cc: Yu Zhao <yuzhao@google.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  mm/shmem.c |    2 --
>  1 file changed, 2 deletions(-)
> 
> --- a/mm/shmem.c~mm-revert-mm-shmem-fix-data-race-in-shmem_getattr
> +++ a/mm/shmem.c
> @@ -1166,9 +1166,7 @@ static int shmem_getattr(struct mnt_idma
>  	stat->attributes_mask |= (STATX_ATTR_APPEND |
>  			STATX_ATTR_IMMUTABLE |
>  			STATX_ATTR_NODUMP);
> -	inode_lock_shared(inode);
>  	generic_fillattr(idmap, request_mask, inode, stat);
> -	inode_unlock_shared(inode);
>  
>  	if (shmem_huge_global_enabled(inode, 0, 0, false, NULL, 0))
>  		stat->blksize = HPAGE_PMD_SIZE;
> _
> 
> Patches currently in -mm which might be from akpm@linux-foundation.org are
> 
> fs-proc-vmcorec-fix-warning-when-config_mmu=n.patch
> mm-revert-mm-shmem-fix-data-race-in-shmem_getattr.patch