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    SubjectRe: Subject: [PATCH] net/ipv6: Use GFP_ATOMIC when a lock is held
    On Sun, 30 May 2010, Eric Dumazet wrote:

    > Le dimanche 30 mai 2010 à 22:50 +0200, Julia Lawall a écrit :
    >
    > > I think the proposed patch does not work, because the for loop overwrites
    > > p. That use of p looks like it is completely local to the for loop, so
    > > perhaps a new variable p1 could be added to be used there?
    >
    > Please do so.
    >
    > I just wanted to tell you changing GFP_KERNEL to GFP_ATOMIC is not an
    > appropriate way to solve this kind of problems. My patch was to get an
    > idea, not a full and tested patch :)

    Looking at it again, there is still a problem, because in the original
    code, the loop:

    for (p = t->prl; p; p = p->next) {
    if (p->addr == a->addr) {
    if (chg) {
    p->flags = a->flags;
    goto out;
    }
    err = -EEXIST;
    goto out;
    }
    }

    could exit with success without the kzalloc ever being called. If the
    kzalloc is moved up, it could fail and then it returns immediately without
    executing the loop. A solution could be to leave the NULL test on p where
    it is, and only move up the kzalloc. Or perhaps the change in behavior
    doesn't matter?

    julia
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