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b=Y7ln+FlbD4PcqCP5yEbB8+z9u5uBHbtgzePE+vl7CzyYQT84HWwiQ9gFE3LdDE6WW kycw/NZCllnvk1C46CYmm/7XuZd4/1gGAZY+2PMKxUmLlIyJqXgGZsAFZqA5FQ/ybP A4/bo86f6tQGFw3JxCxiqBCw9jBmvbMGP4A9+vLw= Date: Mon, 18 May 2026 16:10:12 -0700 From: Andrew Morton To: "Uladzislau Rezki (Sony)" Cc: linux-mm@kvack.org, Baoquan He , LKML , Ido Schimmel , syzbot+8b12fc6e0fb139765b58@syzkaller.appspotmail.com Subject: Re: [PATCH] mm/vmalloc: Do not trigger BUG() on BH disabled context Message-Id: <20260518161012.6f92f9aca2a4db3776c536e1@linux-foundation.org> In-Reply-To: <20260515153009.2296191-1-urezki@gmail.com> References: <20260515153009.2296191-1-urezki@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: mpqjx6upy7mw4jot8nuap94zb34dixta X-Rspamd-Queue-Id: C50A82000D X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1779145814-971211 X-HE-Meta: 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 Gya79PAl vBpvwyg1mq576GdWJUtDsClagYkC9vDbKDcTFpsQ1l9DqvmF3pR65m0fk2CY7WOGi8LpTMLPQStMiPGvYrEERcfpKDBNBjTi5HUfIDKdzS3OyyuNqj3sHU5J+L5nM+e1qRCNVZkrH9wx79YZqhsZq1KMTCGGtUY4NU+uq2pM6Po6zIPj5zS4gHP8oeY/6oxIK8OdvM/QBuNdRSr6RBSizyBewJAkQrhZ+wbvkti8TUq3tGafaa1XeqngQtc0Dbm+C/JbpsYjcg58Nwf3T+0v7q/4l4Q9lJW7nwe2iqQYAbZVGdgFFW4+F5N1vlOjYnjcW+9yF/qGUUCk+zGLNfYuIpBB3Oss2IpGzssmIzkBZNpHuFs0iJnOMECNagikuDQ4kDp/8dY+XYSyfK+DwC0uxCN3TfK1owLQBkecpUYPU36xAqC/jkRVrB98qyW8l70/oUiAo6sKUPu3cCOw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 15 May 2026 17:30:09 +0200 "Uladzislau Rezki (Sony)" wrote: > __get_vm_area_node() currently triggers a BUG() if in_interrupt() > returns true. However, in_interrupt() also reports true when BH > are disabled. > > The bridge code can call rhashtable_lookup_insert_fast() with > bottom halves disabled: > > __vlan_add() > -> br_fdb_add_local() > spin_lock_bh(&br->hash_lock); <-- Disable BH > -> fdb_add_local() > -> fdb_create() > -> rhashtable_lookup_insert_fast() > -> kvmalloc() > -> vmalloc() > -> __get_vm_area_node() > -> BUG_ON(in_interrupt()) > spin_unlock_bh(&br->hash_lock) > > this triggers the BUG() despite the caller not being in NMI or > hard IRQ context. > > Replace the in_interrupt() check with in_nmi() || in_hardirq(). > > Cc: Ido Schimmel > Fixes: c6307674ed82 ("mm: kvmalloc: add non-blocking support for vmalloc") Was added in 6.19 so I assumed we want cc:stable on this. > Reported-by: syzbot+8b12fc6e0fb139765b58@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/all/69ff8c7c.050a0220.1036b8.000b.GAE@google.com/ > Signed-off-by: Uladzislau Rezki (Sony)