Hi, everyone,

We noticed a regression in OpenWrt, with IPv6, which causes a router's client devices to stop receiving the IPv6 default route. I have bisected it down to (rather surprisingly) fc1072d934f687e1221d685cf1a49a5068318f34 ("proc: use the same treatment to check proc_lseek as ones for proc_read_iter et.al"). Reverting the aforementioned commit fixes the issue, of course.

Git bisect log follows:

git bisect start # status: waiting for both good and bad commits # bad: [880e4ff5d6c8dc6b660f163a0e9b68b898cc6310] Linux 6.12.42 git bisect bad 880e4ff5d6c8dc6b660f163a0e9b68b898cc6310 # status: waiting for good commit(s), bad commit known # good: [8f5ff9784f3262e6e85c68d86f8b7931827f2983] Linux 6.12.41 git bisect good 8f5ff9784f3262e6e85c68d86f8b7931827f2983 # good: [dab173bae3303f074f063750a8dead2550d8c782] RDMA/hns: Fix double destruction of rsv_qp git bisect good dab173bae3303f074f063750a8dead2550d8c782 # bad: [11fa01706a4f60e759fbee7c53095ff22eaf1595] PCI: pnv_php: Work around switches with broken presence detection git bisect bad 11fa01706a4f60e759fbee7c53095ff22eaf1595 # bad: [966460bace9e1dd8609c9d44cf4509844daea8bb] perf record: Cache build-ID of hit DSOs only git bisect bad 966460bace9e1dd8609c9d44cf4509844daea8bb # bad: [f63bd615e58f43dbe4b2e4c3f3ffa0bfb7766007] hwrng: mtk - handle devm_pm_runtime_enable errors git bisect bad f63bd615e58f43dbe4b2e4c3f3ffa0bfb7766007 # bad: [9ea3f6b9a67be3476e331ce51cac316c2614a564] pinmux: fix race causing mux_owner NULL with active mux_usecount git bisect bad 9ea3f6b9a67be3476e331ce51cac316c2614a564 # good: [1209e33fe3afb6d9e543f963d41b30cfc04538ff] RDMA/hns: Get message length of ack_req from FW git bisect good 1209e33fe3afb6d9e543f963d41b30cfc04538ff # good: [5f3c0301540bc27e74abbfbe31571e017957251b] RDMA/hns: Fix -Wframe-larger-than issue git bisect good 5f3c0301540bc27e74abbfbe31571e017957251b # bad: [fc1072d934f687e1221d685cf1a49a5068318f34] proc: use the same treatment to check proc_lseek as ones for proc_read_iter et.al git bisect bad fc1072d934f687e1221d685cf1a49a5068318f34 # good: [ec437d0159681bbdb1cf1f26759d12e9650bffca] kernel: trace: preemptirq_delay_test: use offstack cpu mask git bisect good ec437d0159681bbdb1cf1f26759d12e9650bffca # first bad commit: [fc1072d934f687e1221d685cf1a49a5068318f34] proc: use the same treatment to check proc_lseek as ones for proc_read_iter et.al

Please let me know if you need any additional information.

Kind regards,

Rui Salvaterra

Hi Rui, Thanks. I have submitted a patch and I think it can fix this. https://lore.kernel.org/all/20250821105806.1453833-1-wangzijie1@honor.com