Merge branch 'net-smc-fix-use-after-free-in-smc_rx_pipe_buf_release'

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Hidayath Khan says:

====================
net/smc: fix use-after-free in smc_rx_pipe_buf_release()

smc_rx_pipe_buf_release() tests sk_state before taking the socket lock
and then dereferences conn->rmb_desc and conn->lgr. A concurrent close
runs smc_conn_free() in between, which releases those structures. On the
is_reg_err path smcr_buf_unuse() frees the descriptor outright, so this
is a use-after-free.

Patch 2/2 fixes this by taking the socket lock first and testing
conn->freed instead. smc_conn_free() sets that flag before releasing
anything, under the same lock, so the two paths exclude each other.

Patch 1/2 is a prerequisite. conn->freed shares a byte with killed and
out_of_sync as single-bit bitfields. out_of_sync is written from the
receive tasklet without the socket lock, so a concurrent store to freed
from process context can be lost in the read-modify-write. Patch 1/2
gives each flag its own byte so stores do not interfere.
====================

Link: https://patch.msgid.link/20260820074642.966856-1-hidayath@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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This commit is contained in:

Jakub Kicinski 2026-08-24 11:52:02 -07:00

parent 719296c4aa c924884743

commit c745d091fc

2 changed files with 8 additions and 9 deletions

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6

net/smc/smc.h

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11

net/smc/smc_rx.c

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