Sorry for the delayed response.
Yes, you are correct. There is no call from IRQ in dump.
I take back our assertion. Thanks for the insights.
On Wednesday 03 October 2018 05:23 PM, Michal Hocko wrote:
On Wed 03-10-18 17:20:15, Ashish Mhetre wrote:
This doesn't show the backtrace part which contains the allocation
AFAICS.
My bad. Here is a complete dump:
[ 264.082531] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
[ 264.088350] Modules linked in:
[ 264.091406] CPU: 0 PID: 3805 Comm: kworker/0:4 Tainted: G W
3.10.33-g990282b #1
[ 264.099572] Workqueue: events netstat_work_func
[ 264.104097] task: e7b12040 ti: dc7d4000 task.ti: dc7d4000
[ 264.109485] PC is at zs_map_object+0x180/0x18c
[ 264.113918] LR is at zram_bvec_rw.isra.15+0x304/0x88c
[ 264.118956] pc : [<c01581e8>] lr : [<c0456618>] psr: 200f0013
[ 264.118956] sp : dc7d5460 ip : fff00814 fp : 00000002
[ 264.130407] r10: ea8ec000 r9 : ebc93340 r8 : 00000000
[ 264.135618] r7 : c191502c r6 : dc7d4020 r5 : d25f5684 r4 : ec3158c0
[ 264.142128] r3 : 00000200 r2 : 00000002 r1 : c191502c r0 : ea8ec000
--------
[ 265.772426] [<c01581e8>] (zs_map_object+0x180/0x18c) from [<c0456618>]
(zram_bvec_rw.isra.15+0x304/0x88c)
[ 265.781973] [<c0456618>] (zram_bvec_rw.isra.15+0x304/0x88c) from
[<c0456d78>] (zram_make_request+0x1d8/0x378)
[ 265.791868] [<c0456d78>] (zram_make_request+0x1d8/0x378) from [<c02c7afc>]
(generic_make_request+0xb0/0xdc)
[ 265.801588] [<c02c7afc>] (generic_make_request+0xb0/0xdc) from
[<c02c7bb0>] (submit_bio+0x88/0x140)
[ 265.810617] [<c02c7bb0>] (submit_bio+0x88/0x140) from [<c01459d4>]
(__swap_writepage+0x198/0x230)
[ 265.819471] [<c01459d4>] (__swap_writepage+0x198/0x230) from [<c011fc50>]
(shrink_page_list+0x4e0/0x974)
[ 265.828930] [<c011fc50>] (shrink_page_list+0x4e0/0x974) from [<c0120644>]
(shrink_inactive_list+0x150/0x3c8)
[ 265.838736] [<c0120644>] (shrink_inactive_list+0x150/0x3c8) from
[<c0120de8>] (shrink_lruvec+0x20c/0x448)
[ 265.848282] [<c0120de8>] (shrink_lruvec+0x20c/0x448) from [<c012109c>]
(shrink_zone+0x78/0x188)
[ 265.856960] [<c012109c>] (shrink_zone+0x78/0x188) from [<c01212ac>]
(do_try_to_free_pages+0x100/0x544)
[ 265.866246] [<c01212ac>] (do_try_to_free_pages+0x100/0x544) from
[<c0121928>] (try_to_free_pages+0x238/0x428)
[ 265.876140] [<c0121928>] (try_to_free_pages+0x238/0x428) from [<c01179cc>]
(__alloc_pages_nodemask+0x5b0/0x90c)
[ 265.886207] [<c01179cc>] (__alloc_pages_nodemask+0x5b0/0x90c) from
[<c0117d44>] (__get_free_pages+0x1c/0x34)
[ 265.896014] [<c0117d44>] (__get_free_pages+0x1c/0x34) from [<c0844a4c>]
(tcp4_seq_show+0x248/0x4b4)
[ 265.905042] [<c0844a4c>] (tcp4_seq_show+0x248/0x4b4) from [<c017a844>]
(seq_read+0x1e4/0x484)
[ 265.913550] [<c017a844>] (seq_read+0x1e4/0x484) from [<c01a84f0>]
(proc_reg_read+0x60/0x88)
[ 265.921884] [<c01a84f0>] (proc_reg_read+0x60/0x88) from [<c015aa44>]
(vfs_read+0xa0/0x14c)
[ 265.930129] [<c015aa44>] (vfs_read+0xa0/0x14c) from [<c015b0c4>]
(SyS_read+0x44/0x80)
[ 265.937942] [<c015b0c4>] (SyS_read+0x44/0x80) from [<c052e98c>]
(netstat_work_func+0x54/0xec)
[ 265.946450] [<c052e98c>] (netstat_work_func+0x54/0xec) from [<c0086700>]
(process_one_work+0x13c/0x454)
[ 265.955823] [<c0086700>] (process_one_work+0x13c/0x454) from [<c008745c>]
(worker_thread+0x140/0x3dc)
265.965022] [<c008745c>] (worker_thread+0x140/0x3dc) from [<c008cf4c>]
(kthread+0xe0/0xe4)
[ 265.973269] [<c008cf4c>] (kthread+0xe0/0xe4) from [<c000ef98>]
(ret_from_fork+0x14/0x20)
[ 264.148640] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
[ 264.155930] Control: 30c5387d Table: aaf7c000 DAC: fffffffd
This looks like a regular syscall path. How have you concluded this is
due to an IRQ context?
