From c450cc7c7a2bfffe1482abbf88c4a3fab4c0b432 Mon Sep 17 00:00:00 2001 From: VanGiang Nguyen Date: Fri, 25 Oct 2024 08:58:02 +0800 Subject: [PATCH] padata: use integer wrap around to prevent deadlock on seq_nr overflow stable inclusion from stable-v6.6.54 commit 1b8cf11b3ca593a8802a51802cd0c28c38501428 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYQSB CVE: CVE-2024-47739 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1b8cf11b3ca593a8802a51802cd0c28c38501428 -------------------------------- commit 9a22b2812393d93d84358a760c347c21939029a6 upstream. When submitting more than 2^32 padata objects to padata_do_serial, the current sorting implementation incorrectly sorts padata objects with overflowed seq_nr, causing them to be placed before existing objects in the reorder list. This leads to a deadlock in the serialization process as padata_find_next cannot match padata->seq_nr and pd->processed because the padata instance with overflowed seq_nr will be selected next. To fix this, we use an unsigned integer wrap around to correctly sort padata objects in scenarios with integer overflow. Fixes: bfde23ce200e ("padata: unbind parallel jobs from specific CPUs") Cc: Co-developed-by: Christian Gafert Signed-off-by: Christian Gafert Co-developed-by: Max Ferger Signed-off-by: Max Ferger Signed-off-by: Van Giang Nguyen Acked-by: Daniel Jordan Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman Signed-off-by: Cheng Yu --- kernel/padata.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/padata.c b/kernel/padata.c index 29545dd6dd53d..8f0af2c09e17b 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -404,7 +404,8 @@ void padata_do_serial(struct padata_priv *padata) /* Sort in ascending order of sequence number. */ list_for_each_prev(pos, &reorder->list) { cur = list_entry(pos, struct padata_priv, list); - if (cur->seq_nr < padata->seq_nr) + /* Compare by difference to consider integer wrap around */ + if ((signed int)(cur->seq_nr - padata->seq_nr) < 0) break; } list_add(&padata->list, pos); -- Gitee