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c863850ce2
When sctp_wait_for_connect is called to wait for connect ready for sp->strm_interleave in sctp_sendmsg_to_asoc, a panic could be triggered if cpu is scheduled out and the new asoc is freed elsewhere, as it will return err and later the asoc gets freed again in sctp_sendmsg. [ 285.840764] list_del corruption, ffff9f0f7b284078->next is LIST_POISON1 (dead000000000100) [ 285.843590] WARNING: CPU: 1 PID: 8861 at lib/list_debug.c:47 __list_del_entry_valid+0x50/0xa0 [ 285.846193] Kernel panic - not syncing: panic_on_warn set ... [ 285.846193] [ 285.848206] CPU: 1 PID: 8861 Comm: sctp_ndata Kdump: loaded Not tainted 4.19.0-rc7.label #584 [ 285.850559] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [ 285.852164] Call Trace: ... [ 285.872210] ? __list_del_entry_valid+0x50/0xa0 [ 285.872894] sctp_association_free+0x42/0x2d0 [sctp] [ 285.873612] sctp_sendmsg+0x5a4/0x6b0 [sctp] [ 285.874236] sock_sendmsg+0x30/0x40 [ 285.874741] ___sys_sendmsg+0x27a/0x290 [ 285.875304] ? __switch_to_asm+0x34/0x70 [ 285.875872] ? __switch_to_asm+0x40/0x70 [ 285.876438] ? ptep_set_access_flags+0x2a/0x30 [ 285.877083] ? do_wp_page+0x151/0x540 [ 285.877614] __sys_sendmsg+0x58/0xa0 [ 285.878138] do_syscall_64+0x55/0x180 [ 285.878669] entry_SYSCALL_64_after_hwframe+0x44/0xa9 This is a similar issue with the one fixed in Commitca3af4dd28("sctp: do not free asoc when it is already dead in sctp_sendmsg"). But this one can't be fixed by returning -ESRCH for the dead asoc in sctp_wait_for_connect, as it will break sctp_connect's return value to users. This patch is to simply set err to -ESRCH before it returns to sctp_sendmsg when any err is returned by sctp_wait_for_connect for sp->strm_interleave, so that no asoc would be freed due to this. When users see this error, they will know the packet hasn't been sent. And it also makes sense to not free asoc because waiting connect fails, like the second call for sctp_wait_for_connect in sctp_sendmsg_to_asoc. Fixes:668c9beb90("sctp: implement assign_number for sctp_stream_interleave") Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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There are various text files in the Documentation/ subdirectory,
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See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
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the problems which may result by upgrading your kernel.