Messages in this thread | | | Subject | Re: [PATCH] ipc/util.c: sysvipc_find_ipc() incorrectly updates position index | From | Jiri Slaby <> | Date | Tue, 12 May 2020 11:21:59 +0200 |
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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.
Wouldn't it be better to rebase (apply the originally submitted patch) before the XA rewrite and push that one to Linus?
thanks, -- js suse labs
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