CVE-2026-98922

net: emac: move setting of netops to fix crash

State
Published
Severity
Not scored
Published
Oct 23, 2026
Updated
Oct 23, 2026
Reserved
Sep 25, 2026

Read the record on cve.org

Description

In the Linux kernel, the following vulnerability has been resolved:

net: emac: move setting of netops to fix crash

fixes the following crash on driver initialization:

|BUG: Kernel NULL pointer dereference on read at 0x00000158 |Faulting instruction address: 0xc0566b40 |Oops: Kernel access of bad area, sig: 11 [#1] |BE PAGE_SIZE=4K PowerPC 44x Platform |Modules linked in: |CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: GW 7.3.0-rc3+ #1 |Tainted: [W]=WARN |Hardware name: MyBook Live APM821XX 0x12c41c83 PowerPC 44x Platform |NIP: c0566b40 LR: c05648f8 CTR: c04c1e9c |REGS: c1053a20 TRAP: 0300 Tainted: GW (7.3.0-rc3+) |MSR: 0002b000 <CE,EE,FP,ME> CR: 24008808 XER: 00000000 |DEAR: 00000158 ESR: 00000000 |GPR00: c05648f8 c1053b10 c1063600 c1030000 c5ab3000 00000000 [...] |GPR08: 00000002 00000000 00000000 c1053b40 84002808 00000000 [...] |GPR16: cfffd210 00000002 c0beafcc cfffc960 00000000 c1030644 [...] |GPR24: c0beafbc c1037000 00000000 0000000a 00000000 c1030000 [...] |NIP [c0566b40] phy_link_topo_add_phy+0x2c/0x1d0 |LR [c05648f8] phy_attach_direct+0x1a4/0x368 |Call Trace: |[c1053b10] [c0811e04] klist_put+0x54/0xb4 (unreliable) |[c1053b40] [c05648f8] phy_attach_direct+0x1a4/0x368 |[c1053b70] [c0564ae8] phy_connect_direct+0x2c/0x60 |[c1053b90] [c056c7a8] of_phy_connect+0x50/0x74 |[c1053bc0] [c0572a88] emac_probe+0xd50/0x119c |[c1053c90] [c04cb770] platform_probe+0x74/0xa4 |[c1053cb0] [c04c8f08] really_probe+0x120/0x2b0 |[c1053cd0] [c04c9254] __driver_probe_device+0x1bc/0x1fc |[c1053d00] [c04c9334] driver_probe_device+0x38/0xa8 |[c1053d30] [c04c9560] __driver_attach+0xf4/0x10c |[c1053d50] [c04c6af8] bus_for_each_dev+0x68/0xd0 |[c1053d90] [c04c7c34] bus_add_driver+0xcc/0x1ec |[c1053dc0] [c04c9f6c] driver_register+0xcc/0x110 |[c1053de0] [c0aa3f40] emac_init+0x1c4/0x200

This bug showed up starting with v7.3-rc1. At the NIP in phy_link_topo_add_phy() is a netdev_need_ops_lock() check. This was added by the following commit ded86da4bbb7 ("net: ethtool: relax ethnl_req_get_phydev() locking assertion")

The bug shows up because at the time of_phy_connect() was called, the netdev_ops were *not yet* determined. My fix is to move the code that sets netdev_ops+commac.ops+ethtool_ops further up as emac_init_config() derives that by looking at the device-tree and sets the required dev->phy_mode accordingly.

During review, the Sashiko bot's AI stated that the commac assignment became a dead store. Great catch! To keep the original behavior as-is, one mentioned option "set dev->commac.ops = &emac_commac_ops only in the non-gige case?" sounded like a great plan. So the dev->commac.ops assignment for the non-gige-case moves into the else block.

This patch was tested on a WD MyBook Live (RGMII). the device now works again.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

ProductVersions
LinuxLinux
  • ded86da4bbb78cad74cecc368fee3ae3a296e2ca to before c664cca8f622e66bea6a94279ae2611f1d1c0c67Affected
  • ded86da4bbb78cad74cecc368fee3ae3a296e2ca to before 7c9f391ec89cb621d7af375ace2eb9a6248e5b9dAffected
LinuxLinux
  • 7.2Affected
  • before 7.2Not affected
  • 7.2.9 through 7.2.*Not affected
  • 7.3 and laterNot affected

References

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