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linux/include
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Xin Long fbd019737d sctp: avoid running the sctp state machine recursively 
Ying triggered a call trace when doing an asconf testing:

  BUG: scheduling while atomic: swapper/12/0/0x10000100
  Call Trace:
   <IRQ>  [<ffffffffa4375904>] dump_stack+0x19/0x1b
   [<ffffffffa436fcaf>] __schedule_bug+0x64/0x72
   [<ffffffffa437b93a>] __schedule+0x9ba/0xa00
   [<ffffffffa3cd5326>] __cond_resched+0x26/0x30
   [<ffffffffa437bc4a>] _cond_resched+0x3a/0x50
   [<ffffffffa3e22be8>] kmem_cache_alloc_node+0x38/0x200
   [<ffffffffa423512d>] __alloc_skb+0x5d/0x2d0
   [<ffffffffc0995320>] sctp_packet_transmit+0x610/0xa20 [sctp]
   [<ffffffffc098510e>] sctp_outq_flush+0x2ce/0xc00 [sctp]
   [<ffffffffc098646c>] sctp_outq_uncork+0x1c/0x20 [sctp]
   [<ffffffffc0977338>] sctp_cmd_interpreter.isra.22+0xc8/0x1460 [sctp]
   [<ffffffffc0976ad1>] sctp_do_sm+0xe1/0x350 [sctp]
   [<ffffffffc099443d>] sctp_primitive_ASCONF+0x3d/0x50 [sctp]
   [<ffffffffc0977384>] sctp_cmd_interpreter.isra.22+0x114/0x1460 [sctp]
   [<ffffffffc0976ad1>] sctp_do_sm+0xe1/0x350 [sctp]
   [<ffffffffc097b3a4>] sctp_assoc_bh_rcv+0xf4/0x1b0 [sctp]
   [<ffffffffc09840f1>] sctp_inq_push+0x51/0x70 [sctp]
   [<ffffffffc099732b>] sctp_rcv+0xa8b/0xbd0 [sctp]

As it shows, the first sctp_do_sm() running under atomic context (NET_RX
softirq) invoked sctp_primitive_ASCONF() that uses GFP_KERNEL flag later,
and this flag is supposed to be used in non-atomic context only. Besides,
sctp_do_sm() was called recursively, which is not expected.

Vlad tried to fix this recursive call in Commit c078669340 ("sctp: Fix
oops when sending queued ASCONF chunks") by introducing a new command
SCTP_CMD_SEND_NEXT_ASCONF. But it didn't work as this command is still
used in the first sctp_do_sm() call, and sctp_primitive_ASCONF() will
be called in this command again.

To avoid calling sctp_do_sm() recursively, we send the next queued ASCONF
not by sctp_primitive_ASCONF(), but by sctp_sf_do_prm_asconf() in the 1st
sctp_do_sm() directly.

Reported-by: Ying Xu <yinxu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-01 09:18:57 -04:00
..
acpi ACPI: use different default debug value than ACPICA 2019-03-25 10:45:59 +01:00
asm-generic syscalls: Remove start and number from syscall_set_arguments() args 2019-04-05 09:27:23 -04:00
clocksource
crypto
drm drm/atomic-helper: Make atomic_enable/disable crtc callbacks optional 2019-03-29 11:56:52 +01:00
dt-bindings dt-bindings: clock: sifive: add FU540-C000 PRCI clock constants 2019-04-09 20:36:40 -07:00
keys KEYS: trusted: fix -Wvarags warning 2019-04-08 15:58:54 -07:00
kvm ARM: some cleanups, direct physical timer assignment, cache sanitization 2019-03-15 15:00:28 -07:00
linux Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2019-04-26 01:54:42 -04:00
math-emu
media media: include: fix several typos 2019-03-01 09:45:52 -05:00
memory
misc auxdisplay: charlcd: Introduce charlcd_free() helper 2019-03-17 08:48:16 +01:00
net sctp: avoid running the sctp state machine recursively 2019-05-01 09:18:57 -04:00
pcmcia
ras
rdma
scsi
soc IOMMU Updates for Linux v5.1 2019-03-10 12:29:52 -07:00
sound ASoC: core: conditionally increase module refcount on component open 2019-04-08 14:15:44 +07:00
target
trace syscalls: Remove start and number from syscall_get_arguments() args 2019-04-05 09:26:43 -04:00
uapi Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2019-04-19 10:28:27 -07:00
video media updates for v5.1-rc1 2019-03-09 14:45:54 -08:00
xen