kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-11-10 20:48:12 +00:00
Code Issues Releases Packages Activity

tcp: use GFP_ATOMIC in tcp_send_active_reset()

Browse source 
tcp_send_active_reset() can be called from contexts where gfp_any()
(in tcp_disconnect()) or sk->sk_allocation (in __tcp_close() and
mptcp_do_fastclose()) evaluates to GFP_KERNEL, which includes
__GFP_FS and __GFP_DIRECT_RECLAIM.

Allocating with GFP_KERNEL while holding the socket lock (sk_lock) creates
a lockdep dependency:
  sk_lock -> fs_reclaim

This causes false-positive lockdep circular locking warnings with storage
subsystems (such as nvme-tcp) that acquire socket locks in block I/O paths
and invoke tcp_disconnect() or close sockets upon teardown:
  set->srcu -> sk_lock -> fs_reclaim -> elevator_lock -> set->srcu

Active resets are small RST packet headers that should never
enter direct reclaim or block while holding socket locks.

Use sk_gfp_mask(sk, GFP_ATOMIC | __GFP_NOWARN) inside tcp_send_active_reset()
and remove its priority argument. This preserves __GFP_MEMALLOC access
for SOCK_MEMALLOC sockets, suppresses allocation failure warnings,
and aligns with other control packet allocations (e.g. tcp_send_fin(),
__tcp_send_ack(), tcp_xmit_probe_skb()).

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260827095936.551524-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2026-08-27 09:59:36 +00:00 • committed by Jakub Kicinski
commit 18666c73af
6 changed files with 14 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files