In the Linux kernel, the following vulnerability has been resolved:
net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion
rds_ib_xmit_atomic() always programs a masked atomic opcode
(IB_WR_MASKED_ATOMIC_CMP_AND_SWP or IB_WR_MASKED_ATOMIC_FETCH_AND_ADD)
for every RDS atomic cmsg. But the completion-side switch in
rds_ib_send_unmap_op() only handles the non-masked opcodes, so a masked
atomic completion falls through to default and returns rm == NULL while
send->s_op is left set. rds_ib_send_cqe_handler() then dereferences the
NULL rm via rm->m_final_op, oopsing in softirq context. An unprivileged
AF_RDS sendmsg() of an atomic cmsg over an active RDS/IB connection
triggers it; on hardware that natively accepts masked atomics (mlx4,
mlx5) no extra setup is needed.
RDS/IB: rds_ib_send_unmap_op: unexpected opcode 0xd in WR!
Oops: general protection fault [#1] SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197]
RIP: rds_ib_send_cqe_handler+0x25c/0xb10 (net/rds/ib_send.c:282)
Call Trace:
<IRQ>
rds_ib_send_cqe_handler (net/rds/ib_send.c:282)
poll_scq (net/rds/ib_cm.c:274)
rds_ib_tasklet_fn_send (net/rds/ib_cm.c:294)
tasklet_action_common (kernel/softirq.c:943)
handle_softirqs (kernel/softirq.c:573)
run_ksoftirqd (kernel/softirq.c:479)
</IRQ>
Kernel panic - not syncing: Fatal exception in interrupt
Handle the masked atomic opcodes in the same case as the non-masked
ones: they map to the same struct rds_message.atomic union member, so
the existing container_of()/rds_ib_send_unmap_atomic() body is correct
for them.
net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion
rds_ib_xmit_atomic() always programs a masked atomic opcode
(IB_WR_MASKED_ATOMIC_CMP_AND_SWP or IB_WR_MASKED_ATOMIC_FETCH_AND_ADD)
for every RDS atomic cmsg. But the completion-side switch in
rds_ib_send_unmap_op() only handles the non-masked opcodes, so a masked
atomic completion falls through to default and returns rm == NULL while
send->s_op is left set. rds_ib_send_cqe_handler() then dereferences the
NULL rm via rm->m_final_op, oopsing in softirq context. An unprivileged
AF_RDS sendmsg() of an atomic cmsg over an active RDS/IB connection
triggers it; on hardware that natively accepts masked atomics (mlx4,
mlx5) no extra setup is needed.
RDS/IB: rds_ib_send_unmap_op: unexpected opcode 0xd in WR!
Oops: general protection fault [#1] SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197]
RIP: rds_ib_send_cqe_handler+0x25c/0xb10 (net/rds/ib_send.c:282)
Call Trace:
<IRQ>
rds_ib_send_cqe_handler (net/rds/ib_send.c:282)
poll_scq (net/rds/ib_cm.c:274)
rds_ib_tasklet_fn_send (net/rds/ib_cm.c:294)
tasklet_action_common (kernel/softirq.c:943)
handle_softirqs (kernel/softirq.c:573)
run_ksoftirqd (kernel/softirq.c:479)
</IRQ>
Kernel panic - not syncing: Fatal exception in interrupt
Handle the masked atomic opcodes in the same case as the non-masked
ones: they map to the same struct rds_message.atomic union member, so
the existing container_of()/rds_ib_send_unmap_atomic() body is correct
for them.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
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| Linux | Linux | affected |
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Advisories
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Fixes
Solution
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Workaround
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References
History
Wed, 24 Jun 2026 07:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion rds_ib_xmit_atomic() always programs a masked atomic opcode (IB_WR_MASKED_ATOMIC_CMP_AND_SWP or IB_WR_MASKED_ATOMIC_FETCH_AND_ADD) for every RDS atomic cmsg. But the completion-side switch in rds_ib_send_unmap_op() only handles the non-masked opcodes, so a masked atomic completion falls through to default and returns rm == NULL while send->s_op is left set. rds_ib_send_cqe_handler() then dereferences the NULL rm via rm->m_final_op, oopsing in softirq context. An unprivileged AF_RDS sendmsg() of an atomic cmsg over an active RDS/IB connection triggers it; on hardware that natively accepts masked atomics (mlx4, mlx5) no extra setup is needed. RDS/IB: rds_ib_send_unmap_op: unexpected opcode 0xd in WR! Oops: general protection fault [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197] RIP: rds_ib_send_cqe_handler+0x25c/0xb10 (net/rds/ib_send.c:282) Call Trace: <IRQ> rds_ib_send_cqe_handler (net/rds/ib_send.c:282) poll_scq (net/rds/ib_cm.c:274) rds_ib_tasklet_fn_send (net/rds/ib_cm.c:294) tasklet_action_common (kernel/softirq.c:943) handle_softirqs (kernel/softirq.c:573) run_ksoftirqd (kernel/softirq.c:479) </IRQ> Kernel panic - not syncing: Fatal exception in interrupt Handle the masked atomic opcodes in the same case as the non-masked ones: they map to the same struct rds_message.atomic union member, so the existing container_of()/rds_ib_send_unmap_atomic() body is correct for them. | |
| Title | net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-06-24T07:14:28.622Z
Reserved: 2026-06-09T07:44:35.370Z
Link: CVE-2026-52939
Vulnrichment
No data.
NVD
No data.
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.