Messages in this thread | | | Subject | Re: [PATCH] ipc/util.c: sysvipc_find_ipc() incorrectly updates position index | From | Vasily Averin <> | Date | Tue, 12 May 2020 18:45:16 +0300 |
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On 5/12/20 12:21 PM, Jiri Slaby wrote: > On 08. 05. 20, 12:01, Vasily Averin wrote: >> On 5/8/20 9:07 AM, Vasily Averin wrote: >>> On 5/8/20 6:36 AM, Matthew Wilcox wrote: >>>> On Thu, May 07, 2020 at 05:02:42PM -0700, Andrew Morton wrote: >>>>> Here's how I resolved things. Please check? >>>>> >>>>> static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, >>>>> loff_t *new_pos) >>>>> { >>>>> unsigned long index = pos; >>>>> struct kern_ipc_perm *ipc; >>>>> >>>>> rcu_read_lock(); >>>>> ipc = xa_find(&ids->ipcs, &index, ULONG_MAX, XA_PRESENT); >>>>> if (ipc) >>>>> ipc_lock_object(ipc); >>>>> else >>>>> rcu_read_unlock(); >>>>> *new_pos = pos + 1; >>>>> return ipc; >>>>> } >>>> >>>> Surely that should be '*new_pos = index + 1'? Or did I misunderstand >>>> the reasoning behind the other patch? >>> >>> I'm not sure however it looks like xa_find() can return index < pos >> it seems, I was wrong here. >> So I'm agree with Matthew, '*new_pos = index + 1' should be used. > > Any progress on this? 5.7-rc*, 5.4.40, and 5.6.12 are still affected.
Andrew included fix to -mm tree and I hope he'll push it to mainline/stable soon. https://ozlabs.org/~akpm/mmots/broken-out/ipc-utilc-sysvipc_find_ipc-incorrectly-updates-position-index.patch
> Wouldn't it be better to rebase (apply the originally submitted patch) > before the XA rewrite and push that one to Linus? I'm expecting thins too.
Thank you, Vasily Averin
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