Date: Sat, 10 Jul 2021 11:13:05 GMT From: =?utf-8?Q?Stefan E=C3=9Fer?= <se@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 58080fbca09f - main - libalias: fix divide by zero causing panic Message-ID: <202107101113.16ABD5dG009026@gitrepo.freebsd.org>
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The branch main has been updated by se: URL: https://cgit.FreeBSD.org/src/commit/?id=58080fbca09fda6d5f011d37059edbca8ceb4c58 commit 58080fbca09fda6d5f011d37059edbca8ceb4c58 Author: Stefan Eßer <se@FreeBSD.org> AuthorDate: 2021-07-10 11:00:56 +0000 Commit: Stefan Eßer <se@FreeBSD.org> CommitDate: 2021-07-10 11:08:18 +0000 libalias: fix divide by zero causing panic The packet_limit can fall to 0, leading to a divide by zero abort in the "packets % packet_limit". An possible solution would be to apply a lower limit of 1 after the calculation of packet_limit, but since any number modulo 1 gives 0, the more efficient solution is to skip the modulo operation for packet_limit <= 1. Since this is a fix for a panic observed in stable/12, merging this fix to stable/12 and stable/13 before expiry of the 3 day waiting period might be justified, if it works for the reporter of the issue. Reported by: Karl Denninger <karl@denninger.net> MFC after: 3 days --- sys/netinet/libalias/alias_db.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/netinet/libalias/alias_db.c b/sys/netinet/libalias/alias_db.c index c09ad4352ce4..4612b32c139c 100644 --- a/sys/netinet/libalias/alias_db.c +++ b/sys/netinet/libalias/alias_db.c @@ -1769,7 +1769,7 @@ HouseKeeping(struct libalias *la) * Reduce the amount of house keeping work substantially by * sampling over the packets. */ - if (packets % packet_limit == 0) { + if (packet_limit <= 1 || packets % packet_limit == 0) { time_t now; #ifdef _KERNEL
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