-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23200
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6
route. [0]
Commit f72514b3c569 ("ipv6: clear RA flags when adding a static
route") introduced logic to clear RTF_ADDRCONF from existing routes
when a static route with the same nexthop is added. However, this
causes a problem when the existing route has a gateway.
When RTF_ADDRCONF is cleared from a route that has a gateway, that
route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns
true. The issue is that this route was never added to the
fib6_siblings list.
This leads to a mismatch between the following counts:
- The sibling count computed by iterating fib6_next chain, which
includes the newly ECMP-eligible route
- The actual siblings in fib6_siblings list, which does not include
that route
When a subsequent ECMP route is added, fib6_add_rt2node() hits
BUG_ON(sibling-fib6_nsiblings != rt->fib6_nsiblings) because the
counts don't match.
Fix this by only clearing RTF_ADDRCONF when the existing route does
not have a gateway. Routes without a gateway cannot qualify for ECMP
anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing
RTF_ADDRCONF on them is safe and matches the original intent of the
commit.
[0]:
kernel BUG at net/ipv6/ip6_fib.c:1217!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217
[...]
Call Trace:
TASK>
fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532
__ip6_ins_rt net/ipv6/route.c:1351 [inline]
ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946
ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571
inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577
sock_do_ioctl+0xdc/0x300 net/socket.c:1245
sock_ioctl+0x576/0x790 net/socket.c:1366
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-
CVE-2026-23199
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
procfs: avoid fetching build ID while holding VMA lock
Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock
or per-VMA lock, whichever was used to lock VMA under question, to avoid
deadlock reported by syzbot:
- #1 (&mm->mmap_lock){++++}-{4:4}:
__might_fault+0xed/0x170
_copy_to_iter+0x118/0x1720
copy_page_to_iter+0x12d/0x1e0
filemap_read+0x720/0x10a0
blkdev_read_iter+0x2b5/0x4e0
vfs_read+0x7f4/0xae0
ksys_read+0x12a/0x250
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}:
__lock_acquire+0x1509/0x26d0
lock_acquire+0x185/0x340
down_read+0x98/0x490
blkdev_read_iter+0x2a7/0x4e0
__kernel_read+0x39a/0xa90
freader_fetch+0x1d5/0xa80
__build_id_parse.isra.0+0xea/0x6a0
do_procmap_query+0xd75/0x1050
procfs_procmap_ioctl+0x7a/0xb0
__x64_sys_ioctl+0x18e/0x210
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#8);
lock(&mm->mmap_lock);
rlock(&sb->s_type->i_mutex_key#8);
*** DEADLOCK ***
This seems to be exacerbated (as we haven't seen these syzbot reports
before that) by the recent:
777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context")
To make this safe, we need to grab file refcount while VMA is still locked, but
other than that everything is pretty straightforward. Internal build_id_parse()
API assumes VMA is passed, but it only needs the underlying file reference, so
just add another variant build_id_parse_file() that expects file passed
directly.
[akpm@linux-foundation.org: fix up kerneldoc]
-
CVE-2026-23199
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
procfs: avoid fetching build ID while holding VMA lock
Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock
or per-VMA lock, whichever was used to lock VMA under question, to avoid
deadlock reported by syzbot:
- #1 (&mm->mmap_lock){++++}-{4:4}:
__might_fault+0xed/0x170
_copy_to_iter+0x118/0x1720
copy_page_to_iter+0x12d/0x1e0
filemap_read+0x720/0x10a0
blkdev_read_iter+0x2b5/0x4e0
vfs_read+0x7f4/0xae0
ksys_read+0x12a/0x250
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}:
__lock_acquire+0x1509/0x26d0
lock_acquire+0x185/0x340
down_read+0x98/0x490
blkdev_read_iter+0x2a7/0x4e0
__kernel_read+0x39a/0xa90
freader_fetch+0x1d5/0xa80
__build_id_parse.isra.0+0xea/0x6a0
do_procmap_query+0xd75/0x1050
procfs_procmap_ioctl+0x7a/0xb0
__x64_sys_ioctl+0x18e/0x210
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#8);
lock(&mm->mmap_lock);
rlock(&sb->s_type->i_mutex_key#8);
*** DEADLOCK ***
This seems to be exacerbated (as we haven't seen these syzbot reports
before that) by the recent:
777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context")
To make this safe, we need to grab file refcount while VMA is still locked, but
other than that everything is pretty straightforward. Internal build_id_parse()
API assumes VMA is passed, but it only needs the underlying file reference, so
just add another variant build_id_parse_file() that expects file passed
directly.
[akpm@linux-foundation.org: fix up kerneldoc]
-
CVE-2026-23199
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
procfs: avoid fetching build ID while holding VMA lock
Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock
or per-VMA lock, whichever was used to lock VMA under question, to avoid
deadlock reported by syzbot:
- #1 (&mm->mmap_lock){++++}-{4:4}:
__might_fault+0xed/0x170
_copy_to_iter+0x118/0x1720
copy_page_to_iter+0x12d/0x1e0
filemap_read+0x720/0x10a0
blkdev_read_iter+0x2b5/0x4e0
vfs_read+0x7f4/0xae0
ksys_read+0x12a/0x250
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}:
__lock_acquire+0x1509/0x26d0
lock_acquire+0x185/0x340
down_read+0x98/0x490
blkdev_read_iter+0x2a7/0x4e0
__kernel_read+0x39a/0xa90
freader_fetch+0x1d5/0xa80
__build_id_parse.isra.0+0xea/0x6a0
do_procmap_query+0xd75/0x1050
procfs_procmap_ioctl+0x7a/0xb0
__x64_sys_ioctl+0x18e/0x210
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#8);
lock(&mm->mmap_lock);
rlock(&sb->s_type->i_mutex_key#8);
*** DEADLOCK ***
This seems to be exacerbated (as we haven't seen these syzbot reports
before that) by the recent:
777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context")
To make this safe, we need to grab file refcount while VMA is still locked, but
other than that everything is pretty straightforward. Internal build_id_parse()
API assumes VMA is passed, but it only needs the underlying file reference, so
just add another variant build_id_parse_file() that expects file passed
directly.
[akpm@linux-foundation.org: fix up kerneldoc]
-
CVE-2026-23199
•
published on February 14, 2026
In the Linux kernel, the following vulnerability has been resolved:
procfs: avoid fetching build ID while holding VMA lock
Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock
or per-VMA lock, whichever was used to lock VMA under question, to avoid
deadlock reported by syzbot:
- #1 (&mm->mmap_lock){++++}-{4:4}:
__might_fault+0xed/0x170
_copy_to_iter+0x118/0x1720
copy_page_to_iter+0x12d/0x1e0
filemap_read+0x720/0x10a0
blkdev_read_iter+0x2b5/0x4e0
vfs_read+0x7f4/0xae0
ksys_read+0x12a/0x250
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}:
__lock_acquire+0x1509/0x26d0
lock_acquire+0x185/0x340
down_read+0x98/0x490
blkdev_read_iter+0x2a7/0x4e0
__kernel_read+0x39a/0xa90
freader_fetch+0x1d5/0xa80
__build_id_parse.isra.0+0xea/0x6a0
do_procmap_query+0xd75/0x1050
procfs_procmap_ioctl+0x7a/0xb0
__x64_sys_ioctl+0x18e/0x210
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#8);
lock(&mm->mmap_lock);
rlock(&sb->s_type->i_mutex_key#8);
*** DEADLOCK ***
This seems to be exacerbated (as we haven't seen these syzbot reports
before that) by the recent:
777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context")
To make this safe, we need to grab file refcount while VMA is still locked, but
other than that everything is pretty straightforward. Internal build_id_parse()
API assumes VMA is passed, but it only needs the underlying file reference, so
just add another variant build_id_parse_file() that expects file passed
directly.
[akpm@linux-foundation.org: fix up kerneldoc]