bisecting cause commit starting from e42617b825f8073569da76dc4510bfa019b1c35a building syzkaller on b31eda3df81f62eb7efde0c5d7a9f24ee7e34e6f testing commit e42617b825f8073569da76dc4510bfa019b1c35a with gcc (GCC) 8.1.0 kernel signature: 31fe88906cc51332c1f46d69a3805f60c5a30cc0 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: 6966fc9b8181fb7fd947599216cbfec460cc8771 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: 180de7db946c369742826bad918b5402a15e1006 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: 1d89b1391c33947916b090f5e29757b013b92957 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: 5ef132254f3546e558994454ed5939a91fe100f5 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: 27aed0e12e0d1bfbe14d7102b76175685faa7459 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: ade280f64230c21dc8e8f09a8fa157cb9b6bf943 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in corrupted run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 78f8a1d076a0da77d39c92166bb57847a4ec3e58 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: 4b25bb63ac5e6fa562f84e36a26a37919730e986 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 2217dbaf91380380cbfe6d908d02092b55a31af6 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: ea09b1788e63f03e5cfa4231c0bc5fbaa3e6bb06 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: 98a0d36a7d4f198d3cdebb631388a3648c111b2e all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: 8dda4d6893030b39b880bd31dd9ef2bd280436c7 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: ed7a5ccf60901436c5e26c178dc59dad3359432e all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 423f6d13e418205ef21ccbfaba1400cb85d67afb all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.11 testing commit a351e9b9fc24e982ec2f0e76379a49826036da12 with gcc (GCC) 7.3.0 kernel signature: 25e47cf7ee8226c43af87252817032e310476ae5 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.10 testing commit c470abd4fde40ea6a0846a2beab642a578c0b8cd with gcc (GCC) 5.5.0 kernel signature: 6e92830c57ba4fd3c7473cd6729277b7efaba9e1 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: af62b1d9bebec958a9f4ce6506b9c878d6c91402 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel run #8: crashed: BUG: unable to handle kernel run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: 32712ee177991b5655da35e4f6884090d9a2eb1d run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel run #5: crashed: BUG: unable to handle kernel run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: d376d63cb57f974fad5762c89c080f37f14763cf run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: a4e646af0aa7bce8846bc3c97c05caa6a4bb47b9 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #9: crashed: BUG: unable to handle kernel testing release v4.5 testing commit b562e44f507e863c6792946e4e1b1449fbbac85d with gcc (GCC) 5.5.0 kernel signature: c3ed3837e6969162e1204b137534e00160963b85 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel run #8: crashed: BUG: unable to handle kernel run #9: crashed: BUG: unable to handle kernel testing release v4.4 testing commit afd2ff9b7e1b367172f18ba7f693dfb62bdcb2dc with gcc (GCC) 5.5.0 kernel signature: 3dea76462e02d02d8776c2adfa0461abadcca927 all runs: OK # git bisect start b562e44f507e863c6792946e4e1b1449fbbac85d afd2ff9b7e1b367172f18ba7f693dfb62bdcb2dc Bisecting: 6608 revisions left to test after this (roughly 13 steps) [e535d74bc50df2357d3253f8f3ca48c66d0d892a] Merge tag 'docs-4.5' of git://git.lwn.net/linux testing commit e535d74bc50df2357d3253f8f3ca48c66d0d892a with gcc (GCC) 5.5.0 kernel signature: 72fdac4e0292f8d606426678d84967e501893451 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out # git bisect bad e535d74bc50df2357d3253f8f3ca48c66d0d892a Bisecting: 3355 revisions left to test after this (roughly 12 steps) [c17488d06666153a14dd3f21bd10eba58383f6c1] Merge tag 'trace-v4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace testing commit c17488d06666153a14dd3f21bd10eba58383f6c1 with gcc (GCC) 5.5.0 kernel signature: 4a6af111bc7a6bfc4f86db3572e78a961731f695 all runs: OK # git bisect good c17488d06666153a14dd3f21bd10eba58383f6c1 Bisecting: 1610 revisions left to test after this (roughly 11 steps) [ac53b2e053fffc74372da94e734b92f37e70d32c] Merge tag 'for-linus-20160112' of git://git.infradead.org/linux-mtd testing commit ac53b2e053fffc74372da94e734b92f37e70d32c with gcc (GCC) 5.5.0 kernel signature: a514fffe8c3af90b6d8ee8c0e7ebbd61b3ab9a41 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel run #2: crashed: BUG: unable to handle kernel run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel run #6: crashed: BUG: unable to handle kernel run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out # git bisect bad ac53b2e053fffc74372da94e734b92f37e70d32c Bisecting: 895 revisions left to test after this (roughly 10 steps) [841e3ed977e0284e3680d6345d880a64e8072573] Revert "arm64: dts: Add dts files to enable ION on Hi6220 SoC." testing commit 841e3ed977e0284e3680d6345d880a64e8072573 with gcc (GCC) 5.5.0 kernel signature: daabf2706879190d10fcee67f0096b28fbe4170f all runs: OK # git bisect good 841e3ed977e0284e3680d6345d880a64e8072573 Bisecting: 496 revisions left to test after this (roughly 9 steps) [237f38c3b3ab08eadecc89b7c9647b1cdb996bbe] Merge tag 'usb-4.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb testing commit 237f38c3b3ab08eadecc89b7c9647b1cdb996bbe with gcc (GCC) 5.5.0 kernel signature: 21660248a73736874e085f1f77430e9fe73b146e all runs: OK # git bisect good 237f38c3b3ab08eadecc89b7c9647b1cdb996bbe Bisecting: 226 revisions left to test after this (roughly 8 steps) [d6a322774cb7096ca683fc46ddc9482e02ee6133] Merge tag 'dmaengine-4.5-rc1' of git://git.infradead.org/users/vkoul/slave-dma testing commit d6a322774cb7096ca683fc46ddc9482e02ee6133 with gcc (GCC) 5.5.0 kernel signature: dc0d0ea42b4f490534ecb80c7e7ed0ca45b9fd5d run #0: crashed: BUG: unable to handle kernel run #1: crashed: BUG: unable to handle kernel run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #9: crashed: BUG: unable to handle kernel # git bisect bad d6a322774cb7096ca683fc46ddc9482e02ee6133 Bisecting: 138 revisions left to test after this (roughly 7 steps) [39272dde8ffcfd1322209e05f3f8fa4d14f796de] Merge tag 'staging-4.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging testing commit 39272dde8ffcfd1322209e05f3f8fa4d14f796de with gcc (GCC) 5.5.0 kernel signature: 5bbd11fc87852345c956017a07ee0445fce9fb5b run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel run #4: crashed: BUG: unable to handle kernel run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out # git bisect bad 39272dde8ffcfd1322209e05f3f8fa4d14f796de Bisecting: 65 revisions left to test after this (roughly 6 steps) [afd7f88f157796e586fc99d62da13a54024e0731] serial: 8250: move of_serial code to 8250 directory testing commit afd7f88f157796e586fc99d62da13a54024e0731 with gcc (GCC) 5.5.0 kernel signature: 0f3836e191cb32f1bc05b18477b5e82fad71e2de run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel run #5: crashed: BUG: unable to handle kernel run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out # git bisect bad afd7f88f157796e586fc99d62da13a54024e0731 Bisecting: 32 revisions left to test after this (roughly 5 steps) [2cda227bba7e8398c6f8a7792c7f35818187dcc6] serial: 8250_early: do not save and restore IER in write callback testing commit 2cda227bba7e8398c6f8a7792c7f35818187dcc6 with gcc (GCC) 5.5.0 kernel signature: 7cf85216019a10750b3cab76763b9aab760734c8 all runs: OK # git bisect good 2cda227bba7e8398c6f8a7792c7f35818187dcc6 Bisecting: 16 revisions left to test after this (roughly 4 steps) [d97ba9cdae73a69944c6051622c08bfa9016320e] tty: core: Refactor parameters for unset_locked_termios() helper testing commit d97ba9cdae73a69944c6051622c08bfa9016320e with gcc (GCC) 5.5.0 kernel signature: 136d081e0fa67ecdea69e1ca6fa580eb213d7705 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out # git bisect bad d97ba9cdae73a69944c6051622c08bfa9016320e Bisecting: 7 revisions left to test after this (roughly 3 steps) [998b4a4571b87eb6795863e07683fa5d4e0398ba] tty: Improve tty_debug() macro testing commit 998b4a4571b87eb6795863e07683fa5d4e0398ba with gcc (GCC) 5.5.0 kernel signature: f851f044d513184d7b1314ac3415b724ac049e74 run #0: crashed: BUG: unable to handle kernel run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #9: crashed: BUG: unable to handle kernel # git bisect bad 998b4a4571b87eb6795863e07683fa5d4e0398ba Bisecting: 3 revisions left to test after this (roughly 2 steps) [7583633921d54f33e96b65569a0c980ae1d05dba] tty: amba-pl011: add register accessor functions testing commit 7583633921d54f33e96b65569a0c980ae1d05dba with gcc (GCC) 5.5.0 kernel signature: f4555235ff2251f2dce75607804e38232fbcd6ea run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #9: crashed: BUG: unable to handle kernel # git bisect bad 7583633921d54f33e96b65569a0c980ae1d05dba Bisecting: 1 revision left to test after this (roughly 1 step) [004e2ed5cc6d89201140ca96693bf9c0b2945f43] serial: 8250_early: squash wait_for_xmitr() into serial_putc() testing commit 004e2ed5cc6d89201140ca96693bf9c0b2945f43 with gcc (GCC) 5.5.0 kernel signature: 68e1401cc23114639d16084f2378e53cb779f701 all runs: OK # git bisect good 004e2ed5cc6d89201140ca96693bf9c0b2945f43 Bisecting: 0 revisions left to test after this (roughly 0 steps) [bd94c4077a0b2ecc35562c294f80f3659ecd8499] serial: support 16-bit register interface for console testing commit bd94c4077a0b2ecc35562c294f80f3659ecd8499 with gcc (GCC) 5.5.0 kernel signature: 47d856bf66eb3c7760c5578f99b1f9fb0088ff48 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #2: crashed: BUG: unable to handle kernel run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out run #8: crashed: BUG: unable to handle kernel run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out # git bisect bad bd94c4077a0b2ecc35562c294f80f3659ecd8499 bd94c4077a0b2ecc35562c294f80f3659ecd8499 is the first bad commit commit bd94c4077a0b2ecc35562c294f80f3659ecd8499 Author: Masahiro Yamada Date: Wed Oct 28 12:46:05 2015 +0900 serial: support 16-bit register interface for console Currently, 8-bit (MMIO) and 32-bit (MMIO32) register interfaces are supported for the 8250 console, but the 16-bit (MMIO16) is not. The 8250 UART device on my board is connected to a 16-bit bus and my main motivation is to use earlycon with it. (Refer to arch/arm/boot/dts/uniphier-support-card.dtsi) Signed-off-by: Masahiro Yamada Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman Documentation/kernel-parameters.txt | 9 +++++---- drivers/tty/serial/8250/8250_core.c | 7 ++++--- drivers/tty/serial/8250/8250_early.c | 5 +++++ drivers/tty/serial/8250/8250_port.c | 20 ++++++++++++++++++++ drivers/tty/serial/earlycon.c | 15 +++++++++++---- drivers/tty/serial/of_serial.c | 3 +++ drivers/tty/serial/serial_core.c | 9 +++++++-- include/linux/serial_core.h | 1 + include/uapi/linux/serial.h | 1 + 9 files changed, 57 insertions(+), 13 deletions(-) kernel signature: 47d856bf66eb3c7760c5578f99b1f9fb0088ff48 previous signature: 68e1401cc23114639d16084f2378e53cb779f701 revisions tested: 37, total time: 5h12m57.114603357s (build: 2h30m25.21774839s, test: 2h39m36.214815846s) first bad commit: bd94c4077a0b2ecc35562c294f80f3659ecd8499 serial: support 16-bit register interface for console cc: ["corbet@lwn.net" "gregkh@linuxfoundation.org" "jslaby@suse.com" "linux-api@vger.kernel.org" "linux-doc@vger.kernel.org" "linux-kernel@vger.kernel.org" "linux-serial@vger.kernel.org" "peter@hurleysoftware.com" "yamada.masahiro@socionext.com"] crash: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out bond0: Enslaving bond_slave_0 as an active interface with an up link IPv6: ADDRCONF(NETDEV_UP): bond_slave_1: link is not ready bond0: Enslaving bond_slave_1 as an active interface with an up link IPVS: Creating netns size=2712 id=7 IPVS: ftp: loaded support on port[0] = 21 BUG: unable to handle kernel NULL pointer dereference at 0000000000000003 IP: [] writew arch/x86/include/asm/io.h:65 [inline] IP: [] mem16_serial_out+0x14/0x20 drivers/tty/serial/8250/8250_port.c:374 PGD b707b067 PUD b7140067 PMD 0 Oops: 0002 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 5841 Comm: syz-executor.0 Not tainted 4.4.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8800b8848600 ti: ffff88012a96c000 task.ti: ffff88012a96c000 RIP: 0010:[] [] writew arch/x86/include/asm/io.h:65 [inline] RIP: 0010:[] [] mem16_serial_out+0x14/0x20 drivers/tty/serial/8250/8250_port.c:374 RSP: 0018:ffff88012a96fca0 EFLAGS: 00010206 RAX: 000000000000000a RBX: ffffffff8449b720 RCX: 0000000000000000 RDX: 00000000000000bf RSI: 0000000000000003 RDI: ffffffff8449b720 RBP: ffff88012a96fca0 R08: ffffffff82e9a9fc R09: 0000000000000000 R10: ffffffff82e9a9eb R11: 0000000000000000 R12: ffff8800b46fa000 R13: 0000000000000001 R14: ffff8800b46fa000 R15: ffffffff8449b720 FS: 00007fb291ccd700(0000) GS:ffff88012c000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000003 CR3: 00000000b707a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff88012a96fcd8 ffffffff81a4d3c1 ffff88021a1d89a8 ffff8800b46fa000 0000000000000001 ffff8800b46fa000 ffffffff8449b720 ffff88012a96fce8 ffffffff81a4d5a6 ffff88012a96fd20 ffffffff81a47bfd ffff88021a1d89a8 Call Trace: [] serial_port_out include/linux/serial_core.h:260 [inline] [] serial8250_do_startup+0x451/0x620 drivers/tty/serial/8250/8250_port.c:1849 [] serial8250_startup+0x16/0x20 drivers/tty/serial/8250/8250_port.c:2075 [] uart_port_startup drivers/tty/serial/serial_core.c:163 [inline] [] uart_startup.part.15+0x7d/0x190 drivers/tty/serial/serial_core.c:210 [] uart_startup drivers/tty/serial/serial_core.c:772 [inline] [] uart_set_info drivers/tty/serial/serial_core.c:916 [inline] [] uart_set_info_user drivers/tty/serial/serial_core.c:939 [inline] [] uart_ioctl+0x68f/0xaf0 drivers/tty/serial/serial_core.c:1232 [] tty_ioctl+0x385/0xe10 drivers/tty/tty_io.c:2942 [] vfs_ioctl fs/ioctl.c:43 [inline] [] do_vfs_ioctl+0x2dd/0x530 fs/ioctl.c:607 [] SYSC_ioctl fs/ioctl.c:622 [inline] [] SyS_ioctl+0x74/0x80 fs/ioctl.c:613 [] entry_SYSCALL_64_fastpath+0x16/0x76 Code: 89 e5 d3 e6 48 63 f6 48 03 77 40 88 16 5d c3 0f 1f 84 00 00 00 00 00 0f b6 8f c1 00 00 00 55 48 89 e5 d3 e6 48 63 f6 48 03 77 40 <66> 89 16 5d c3 0f 1f 80 00 00 00 00 0f b6 8f c1 00 00 00 55 48 RIP [] mem16_serial_out+0x14/0x20 drivers/tty/serial/8250/8250_port.c:374 RSP CR2: 0000000000000003 ---[ end trace 314bf364f7014a3c ]---