CVE-2025-71293: drm/amdgpu/ras: Move ras data alloc before bad page check

CVE-2025-71293: drm/amdgpu/ras: Move ras data alloc before bad page check

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

drm/amdgpu/ras: Move ras data alloc before bad page check

In the rare event if eeprom has only invalid address entries,
allocation is skipped, this causes following NULL pointer issue
[  547.103445] BUG: kernel NULL pointer dereference, address: 0000000000000010
[  547.118897] #PF: supervisor read access in kernel mode
[  547.130292] #PF: error_code(0x0000) - not-present page
[  547.141689] PGD 124757067 P4D 0
[  547.148842] Oops: 0000 [#1] PREEMPT SMP NOPTI
[  547.158504] CPU: 49 PID: 8167 Comm: cat Tainted: G           OE      6.8.0-38-generic #38-Ubuntu
[  547.177998] Hardware name: Supermicro AS -8126GS-TNMR/H14DSG-OD, BIOS 1.7 09/12/2025
[  547.195178] RIP: 0010:amdgpu_ras_sysfs_badpages_read+0x2f2/0x5d0 [amdgpu]
[  547.210375] Code: e8 63 78 82 c0 45 31 d2 45 3b 75 08 48 8b 45 a0 73 44 44 89 f1 48 8b 7d 88 48 89 ca 48 c1 e2 05 48 29 ca 49 8b 4d 00 48 01 d1 <48> 83 79 10 00 74 17 49 63 f2 48 8b 49 08 41 83 c2 01 48 8d 34 76
[  547.252045] RSP: 0018:ffa0000067287ac0 EFLAGS: 00010246
[  547.263636] RAX: ff11000167c28130 RBX: ff11000127600000 RCX: 0000000000000000
[  547.279467] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ff11000125b1c800
[  547.295298] RBP: ffa0000067287b50 R08: 0000000000000000 R09: 0000000000000000
[  547.311129] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[  547.326959] R13: ff11000217b1de00 R14: 0000000000000000 R15: 0000000000000092
[  547.342790] FS:  0000746e59d14740(0000) GS:ff11017dfda80000(0000) knlGS:0000000000000000
[  547.360744] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  547.373489] CR2: 0000000000000010 CR3: 000000019585e001 CR4: 0000000000f71ef0
[  547.389321] PKRU: 55555554
[  547.395316] Call Trace:
[  547.400737]  <TASK>
[  547.405386]  ? show_regs+0x6d/0x80
[  547.412929]  ? __die+0x24/0x80
[  547.419697]  ? page_fault_oops+0x99/0x1b0
[  547.428588]  ? do_user_addr_fault+0x2ee/0x6b0
[  547.438249]  ? exc_page_fault+0x83/0x1b0
[  547.446949]  ? asm_exc_page_fault+0x27/0x30
[  547.456225]  ? amdgpu_ras_sysfs_badpages_read+0x2f2/0x5d0 [amdgpu]
[  547.470040]  ? mas_wr_modify+0xcd/0x140
[  547.478548]  sysfs_kf_bin_read+0x63/0xb0
[  547.487248]  kernfs_file_read_iter+0xa1/0x190
[  547.496909]  kernfs_fop_read_iter+0x25/0x40
[  547.506182]  vfs_read+0x255/0x390

This also result in space left assigned to negative values.
Moving data alloc call before bad page check resolves both the issue.

The Linux kernel CVE team has assigned CVE-2025-71293 to this issue.


Affected and fixed versions
===========================

	Fixed in 6.18.16 with commit 0b7f78caeffa51a1afa521c284e863ec3b5a36df
	Fixed in 6.19.6 with commit 5c685235b60459381e959109b416a63db4d8dbac
	Fixed in 7.0 with commit bd68a1404b6fa2e7e9957b38ba22616faba43e75

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-71293
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/0b7f78caeffa51a1afa521c284e863ec3b5a36df
	https://git.kernel.org/stable/c/5c685235b60459381e959109b416a63db4d8dbac
	https://git.kernel.org/stable/c/bd68a1404b6fa2e7e9957b38ba22616faba43e75