Hi, I am using Kernel: 4.9.217 for one of the ARM32 boards for Qualcomm SOC. https://github.com/android-linux-stable/msm-4.9 But I think this is a general bug applicable to :Kernel 4.9 under fs/sysfs/file.c So, I wanted to quickly check here if others are familiar with this issue and if it is fixed already. Note, this issue does not occur in 4.14 Kernel. When I execute below command, the Kernel is crashing. I tried to add few debug prints to find more details. I see that the ops->show pointer is not valid (seems corrupted). So I wanted to understand how this can happen only for this particular node. Other sysfs entries are working fine. # cat /sys/power/rpmh_stats/master_stats [ 140.873100] sysfs_kf_seq_show: Enter - 1 [ 140.873139] sysfs_kf_seq_show: Enter - 2 : buff: e6aa0e1e, ops->show: 1482eca6 [ 140.876229] sysfs_kf_seq_show: Enter - 3 : Inside ops->show [ 140.885040] Unable to handle kernel paging request at virtual address db74fd70 [ 140.888595] pgd = 29c1de54 [ 140.895874] [db74fd70] *pgd=9b60041e(bad) [ 140.902561] Internal error: Oops: 8000000d [#1] PREEMPT ARM [ 140.902650] Modules linked in: bluetooth_power(O) emac_dwc_eqos(O) evdev [ 140.914712] CPU: 0 PID: 1990 Comm: cat Tainted: G W O 4.9.217 #22 [ 140.922014] task: 4e6f2759 task.stack: bce99fef [ 140.930428] PC is at 0xdb74fd70 [ 140.934683] LR is at sysfs_kf_seq_show+0x13c/0x1d8 [ 140.937807] pc : [<db74fd70>] lr : [<c0286028>] psr: a00f0013 [ 140.937807] sp : d8a29cb0 ip : 00000000 fp : 00000000 [ 140.942676] r10: db74e880 r9 : d9fef500 r8 : c0c21e38 [ 140.954038] r7 : 00001000 r6 : c1f9a000 r5 : d9fef680 r4 : c0399830 [ 140.959249] r3 : db74fd70 r2 : c1f9a000 r1 : db74e850 r0 : db74e880 [ 140.965847] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 140.972357] Control: 10c53c7d Table: 99f00059 DAC: 00000051 [ 140.979559] [ 140.979559] PC: 0xdb74fcf0: [ 140.985285] fcf0 0fe55620 00000000 c0c14990 00000000 00001000 00000000 00000000 00000000 [ 140.997604] fd10 c135ea1c 80800052 00004fd6 00000000 00000004 00000000 de1e0410 c0f44926 [ 141.005765] fd30 dbcd91a1 00000000 00000000 00000000 555832c2 00000000 00000000 db74fec0 [ 141.013924] fd50 de1cf000 00000000 00000000 00000000 db7a4418 41ed0011 00004fd7 00000000 [ 141.022084] fd70 00000003 00000000 de3b3000 c0f44926 db890ec0 00000000 00000000 00000000 [ 141.030243] fd90 555832c2 00000000 00000001 db74fdd0 de1cf000 00000000 00000000 00000000 [ 141.038404] fdb0 db74e840 41ed0011 00004fd8 00000000 00000008 00000000 db74fd70 c0f44926 [ 141.046563] fdd0 00000001 00000000 00000000 00000000 555832c2 00000000 00000001 db74ff10 [ 141.054724] [ 141.054724] LR: 0xc0285fa8: [ 141.054816] 5fa8 e0427003 23a06000 30866003 e3570a01 3585200c 3a000032 e5983000 e1a02006 [ 141.067136] 5fc8 e59f10c4 e59f00dc ebfced74 e3a01a01 e1a00006 eb044487 e3560000 1a000003 [ 141.075296] 5fe8 e3a02061 e59f10a0 e59f00bc eaffffc2 e5984000 e3540000 0a00000d e59f1088 [ 141.083455] 6008 e59f00a8 ebfced65 e5991000 e5983000 e1a02006 e1a0000a e5911040 e12fff33 [ 141.091616] 6028 e3500000 b8bd87f0 e3500a01 ba00000c ea000007 e3a02070 e59f104c e59f0070 [ 141.099775] 6048 ebfced56 e3570a01 b5953004 b585300c ba00000b e59f005c e5981000 ebfbecfc [ 141.107934] 6068 e3000fff e595300c e0800003 e5953004 e1500003 9585000c 9a000001 e7f001f2 [ 141.116095] 6088 eaffffc5 e3a00000 e8bd87f0 c0c1484f c0efab69 c0efab84 c0efab9e c0efaaf9 [ 141.124256] [ 141.124256] SP: 0xd8a29c30: [ 141.124347] 9c30 00000000 00000000 c1460a0c 0000002f 00000051 bf000000 db74fd70 db74fd70 [ 141.136668] 9c50 a00f0013 ffffffff d8a29c94 c010c008 db74e880 db74e850 c1f9a000 db74fd70 [ 141.144828] 9c70 c0399830 d9fef680 c1f9a000 00001000 c0c21e38 d9fef500 db74e880 00000000 [ 141.152986] 9c90 00000000 d8a29cb0 c0286028 db74fd70 a00f0013 ffffffff 00000051 00000000 [ 141.161147] 9cb0 d9fef680 00001000 00000000 00000001 d9fb1000 d8a29de0 d9ffe800 c02409ac [ 141.169307] 9cd0 d9fef6b0 d9ffe808 00000000 00000000 d8a29d20 d9ffe800 d9ffe800 d9ffe800 [ 141.177466] 9cf0 00000000 00000000 00001000 d8a29de0 d8a29d20 c02854c0 bf000000 c021f83c [ 141.185626] 9d10 d8a29d1c d8a29d20 c1416c10 d9fef700 00000002 00000000 00010000 d9fef700 [ 141.193788] Process cat (pid: 1990, stack limit = 0xcdf38e89) [ 141.193884] Stack: (0xd8a29cb0 to 0xd8a2a000) [ 141.199612] 9ca0: d9fef680 00001000 00000000 00000001 [ 141.203959] 9cc0: d9fb1000 d8a29de0 d9ffe800 c02409ac d9fef6b0 d9ffe808 00000000 00000000 [ 141.212119] 9ce0: d8a29d20 d9ffe800 d9ffe800 d9ffe800 00000000 00000000 00001000 d8a29de0 [ 141.220279] 9d00: d8a29d20 c02854c0 bf000000 c021f83c d8a29d1c d8a29d20 c1416c10 d9fef700 [ 141.228439] 9d20: 00000002 00000000 00010000 d9fef700 00000010 de001e40 d9ffd940 00000040 [ 141.236598] 9d40: de001e40 c020cc4c 00000200 064200ca 00000000 0000000f d9f69000 00010000 [ 141.244758] 9d60: 00001000 c1416c10 024200c0 c0c103a4 d9f69000 c03a8b9c 00010000 d8a29ddc [ 141.252919] 9d80: d8a29dd8 d8a29de8 d9f69000 d9ffd940 d9ffe800 c03aaef0 00000000 d8a29e00 [ 141.261077] 9da0: ffffe000 00000000 00000010 d8a29ec0 d9ffe800 c021f8cc d8a29de0 00000000 [ 141.269237] 9dc0: 00000010 c024cb90 00000000 c1ecb000 00000001 d9ffd940 d9ffd940 00000000 [ 141.277396] 9de0: 00000000 00000000 00000008 00000000 01000000 d9f69000 00000000 00000000 [ 141.285556] 9e00: d9fb1000 00001000 c1b31000 00001000 d9f3a000 00001000 d9fb0000 00001000 [ 141.293716] 9e20: d9f48000 00001000 d9fbe000 00001000 d9fb2000 00001000 d9f5a000 00001000 [ 141.301877] 9e40: d9f49000 00001000 d9f38000 00001000 d9f39000 00001000 d9f2e000 00001000 [ 141.310037] 9e60: d9f2f000 00001000 d9f28000 00001000 d9f29000 00001000 d9f0a000 00001000 [ 141.318195] 9e80: d8a29ec0 d8a29ef0 d9f69000 00000000 d9ffe800 01000000 00000000 c024d438 [ 141.326355] 9ea0: 00000000 c024c8cc 00000000 c034accc 00000000 00000000 00000002 c19c1c00 [ 141.334515] 9ec0: 00000000 00000000 c1055150 d9ffe800 d8a29f40 00000000 00000000 00000000 [ 141.342674] 9ee0: c19c1c00 7fffffff 00000000 c024ca38 01000000 01000000 00000000 c19c1c00 [ 141.350834] 9f00: 00000000 00000000 d8a29f48 00000000 00000000 00000000 00000000 c19c1c00 [ 141.358994] 9f20: d9ffe800 00000000 01000000 c021fd08 01000000 00000000 d9ffe800 c1f9a000 [ 141.367154] 9f40: 00000000 00000000 00000000 00000000 00000020 00000000 00000000 01000000 [ 141.375313] 9f60: 000000ef 00000000 d8a28000 000000ef be855bb4 c0220688 7fffffff 00000000 [ 141.383473] 9f80: 01000000 00000000 01000000 01000000 00000000 01000000 000000ef c0107a84 [ 141.391633] 9fa0: d8a28000 c01078c0 01000000 00000000 00000001 00000003 00000000 01000000 [ 141.399793] 9fc0: 01000000 00000000 01000000 000000ef 00000001 00000001 00000000 be855bb4 [ 141.407952] 9fe0: 7f696ad4 be855ba4 7f5c82fd b6e87358 600f0030 00000001 00000000 00000000 [ 141.416126] [<c0286028>] (sysfs_kf_seq_show) from [<c02409ac>] (seq_read+0x264/0x488) [ 141.424276] [<c02409ac>] (seq_read) from [<c021f83c>] (do_readv_writev+0x2a0/0x2ec) [ 141.432085] [<c021f83c>] (do_readv_writev) from [<c021f8cc>] (vfs_readv+0x44/0x4c) [ 141.439550] [<c021f8cc>] (vfs_readv) from [<c024cb90>] (default_file_splice_read+0x140/0x260) [ 141.447191] [<c024cb90>] (default_file_splice_read) from [<c024c8cc>] (splice_direct_to_actor+0xe4/0x1c0) [ 141.455785] [<c024c8cc>] (splice_direct_to_actor) from [<c024ca38>] (do_splice_direct+0x90/0xa8) [ 141.465332] [<c024ca38>] (do_splice_direct) from [<c021fd08>] (do_sendfile+0x1b8/0x2d8) [ 141.474185] [<c021fd08>] (do_sendfile) from [<c0220688>] (SyS_sendfile64+0xb0/0x13c) [ 141.481915] [<c0220688>] (SyS_sendfile64) from [<c01078c0>] (ret_fast_syscall+0x0/0x28) [ 141.489898] Code: db7a4418 41ed0011 00004fd7 00000000 (00000003) [ 141.497619] ---[ end trace 1ad2096094348e6a ]--- [ 141.503906] Kernel panic - not syncing: Fatal exception -------------- Corresponding code is here: https://github.com/android-linux-stable/msm-4.9/blob/kernel.lnx.4.9.r11-rel/fs/sysfs/file.c If anybody is familiar with this issue please let us know. Thanks, Pintu
